We tried to collect interesting facts about critters
Our sources are mainly Wikipedia, Google and Books. We tried to verify facts in more sources but please inform us if you find mistakes, Special thank you to Silvia and Andrea for the critter tips selection, so here we share for you divers.
It is a coral in the Actiniaria Or After but it is a solitary big polyp. At the end of each tentacle it has stinging nematocysts that paralyze small fishes and invertebrates and bring them to the mouth that is in the center. They can change their location, but they do this rarely and slowly, 2/4 cm per hour. Predators can be some kind of nudibranch, sea stars and fish.
- ANEMONE FISH
Total of 28 around the world, in tropical areas but not found in the Atlantic Ocean. They live in symbiosis with its anemone for cleaning, protection and nutrition.
Usually in one anemone there is a dominant couple plus smaller juvenile males. The exception is the Spinecheek anemone fish which normally tolerates only two fish in the same anemone. Rarely we can see a second smaller male. All the anemone fish are born males and during their life can change sex if needed; when the female dies, the bigger male becomes a female.
Different from butterfly fish with a bigger body and spines on the gills covers. It lives mostly solitary or in territorial couples but some species, they live in a harem with a dominant male. Females can become male when needed. When young it can act as a cleaner. They have a particular pattern to confuse potential predators. Juveniles have brilliant patterns and can live extremely deep or secretively in the back of caves. It eats algae, zooplankton, tunicates, sponges, invertebrates.
They Live in a harem with a dominant male, sometimes in huge feeding aggregations. Inside a normal harem there is the dominant male, a few lesser males and lots of females and juveniles.
They all begin life as female and during their life, influenced by social or environmental cues, change into males. The dominant male keeps control by aggressively overpowering the lesser males.
- ASCIDIANS – TUNICATES
It is a filter feeder animal and it can be solitary or in colonies. They are hermaphroditic. It has two openings called sephons. It takes inside the water from one of them and it expels the filtered water from the second. Inside it hash air, like cilia that capture nutrients, usually planktonic particles. To survive it needs to filter one body volume of water per second. Nudibranchs are known predators of tunicates. Tunicates are the invertebrates group most closely related to humans. We are both in the phylum: Cordata. That’s because they have spinal cords during larval phase. In Australia, the tunicates have evolved a little further and have been seen to watch cricket, drink beer and call each other ‘mate’.
Up to 2m long, it has savagely pointed teeth and lives a mostly pelagic life in blue water but can be seen close to the reef sometimes. It can swim 43 km per hour. While the adult is solitary, the younger barracudas are often seen in a school.
- BASKET SEA STAR
It is a nocturnal sea star. The tentacles can be up to 70 cm long and the central disc can reach 14 cm across. It eats planktonic prey up to 3 cm long. Using its arms, it captures the prey and immobilizes them with a special mucus and then brings them into the mouth, in the center of the disc. It can live up to five years. It closes itself for defense. They have few predators but have been seen to be eaten by some fish and crabs.
- BLACK TIP SHARK (Sharks in general)
Sharks are known to have existed 420 million years ago, but have evolved a little further in to their present forms. It has a cartilaginous skeleton and 7 senses. Pelagic species are able to detect in the water 1 part of blood per million parts of water and can then determinate the direction of the scent and follow it’s trail over long distances. All sharks have electroreceptive organs (ampullae of Lorenzini) which detect the electromagnetic fields that all living things produce. Pelagic species such as Hammerheads which migrate huge distances may also use this sense also for orientation by detecting the magnetic field of the earth.
Sharks have sensitive lateral lines detecting vibration in the water. Many sharks need to swim constantly to oxygenate the body as they cannot pump their gills. However reef sharks such as the White tip are often observed resting on the bottom.
Every year 100 million sharks are killed by humans.
- BLENNY VS GOBY
The visible difference between a blenny and a goby is that the blenny has a single long dorsal fin while the goby has a two-part dorsal fins. The only exception is the triplefin blenny.
- BLUEFIN TREVALLY
It is a strong predator, with specialised hunting techniques.
– aggressive mid water attack: often it hunts in groups to isolate the prey, rushing in and trying to separate individual fish from the protection of the school.
– reef ambushing: it can change color to camouflage with the reef
– interaction with other species (ex. Sea Krait): in remote reefs in Indonesia it has been observed to hunt in groups with many sea kraits. While the sea kraits are inside the reef crevasses to catch their own prey, the trevallies wait outside looking for escaping fish.
– following other predators to scavenge or steal food. Look for small blue-fin trevally following goatfish and trying to snatch molluscs that the goatfish might discover.
When young or during the night it is often in schools while the adult is often solitary.
- BLUE RING OCTOPUS
One of the most venomous marine animals. Despite its small size, it carries enough poison to kill 26 Humans within minutes. The bite is often painless but quickly leads to paralysis. If it feels threatened it shows the blue rings but only if cornered and touched would they try to bite. The poison is the same tetrodotoxin used by puffer fishes and is created with a special bacteria.
- BLUE SPOTTED STINGRAY
They are ovoviviparous so they give birth to live babies. Can have up to 7 babies. Differently from other sting rays, it doesn’t often bury itself, just to hide from predators, not for hunting. It is a relative of sharks. The teeth are fused in two plaques to break the shells of mollusks and crustaceans, but it eats also fishes occasionally.
As its eyes are located on the upper part of the body, it normally finds the prey using the smell sense and its electroreceptors (ampullae of Lorenzini) to detect life and movements.
Bright colors are warnings for its 2 venomous spines on the tail.
Predators: sharks and larger grouper
- BOX FISH
It is protected by a bony carapace.
It swims with its dorsal, anal and pectoral fins while the tail is used just to change direction.
It eats invertebrates as well as sponges, tunicates and algaes.
It secretes a chemical toxin from their skin when under stress. When this toxic mucous is released in the water it effects negatively any fish in the area. This toxin is also toxic to itself so this fish is very difficult to keep in aquariums as it is constantly committing suicide.
- BUTTERFLY FISH
120 species are divided in to coral or zooplankton feeders.
Most of the 1st category eats coral polyps, is territorial and solitary until it finds a partner for the rest of its life.
The 2nd category lives in schools and is found on reefs exposed to current to feed on zooplankton.
Underwater biodiversity levels are measured on the number of different marine species. Butterfly fish have different shaped mouths to feed on different coral species. Therefore a larger diversity in butterfly fish is an indicator of coral diversity and demonstrates the health of the reef.
Its defense from predators comes from the color pattern. Eye stripes and false eye spots on the body confuse the predator; when it is about to catch a butterfly fish it doesn’t understand in which direction it wants to go to escape from it. Often paired, if they come together the false eyes may also look like a larger fish. They usually change colour at night to become much darker than during the day.
- CARDINAL FISH
It’s a nocturnal fish. In the daylight it lives in aggregations or in pairs in the protection of hard corals and crevices. At dusk it leaves the refuge to feed on zooplankton. The male incubates the eggs inside the mouth.
Sometimes the Pajama Cardinal fish has been observed in the same habitat as the Mandarin Fish.
- CLEANER WRASSE
It lives only by its cleaning work. When visitors come to the cleaning station the wrasse performs a dance, like motion to greet the visitors. The fishes recognize the cleaner from its movements and its lateral stripe.
The busiest moment of the day is the morning when many fishes come out from the crevices after being inside it to sleep. They search for a cleaner to free themselves from the parasites that infect their skin while they are resting at night. A species of blenny mimics the cleaner wrasse to get close enough to the fish to bite and eat a piece of the victim instead of cleaning.
- COMET FISH
It is a nocturnal fish.
They catch their prey by approaching it side ways and waiting for the pray to try to escape. The fish is oval with no real change in shape between the head and tail ends. The cornered fish will try to escape by either swimming to the left or to the right. 50% of the time, this escape route is towards the comet fish’s mouth.
For defense it hides half of the body in a crevasse and leaves the tail out. The black body with white spots and a false eye is said to mimic a white mouth moray eel head.
- CONVICT BLENNY
It mimics the venomous striped eel catfish in it’s juvenile state with a similar shape, color, pattern and behavior: during the day, when they are young, they form a big school like the catfishes do. During the night they hide themselves inside a burrow in the sand. They have been observed coming out all together from the burrow when an adult inside pushed them out. The adult is thought to live the all life inside the burrow, perhaps feeding with the help of the young.
- CRESCENT TAIL BIG EYE
It is a nocturnal fish as indicated by its large eyes. During the day it stays close to the reef and after sunset it moves to the open water to feed on zooplankton and small squids, octopuses, shrimps and fishes. It can be seen in dark red color or pale pink, depending on its mood. Often can be observed turning into the dark red when it feels threatened.
Echinoderms are related to starfish. They are filter feeders and use their tentacles (from 2 to 200) to capture plankton. Most of them have modified arms called cirri to hold themselves in place on the reef. At night some crinoids climb on top of gorgonians or part of the reef more exposed to the current. Most of them can swim by moving their tentacles.
- CROCODILE FISH
It is a close relative of the scorpionfish. Its hunting technique is very simple: just be camouflaged and wait for a fish passing by close enough to its mouth. It has an elaborated curtain of tassels that expand or contract, depending on the intensity of the sunlight. It can be observed easily because it doesn’t move even if you are so close that you could touch it. Like many fish that sit on the bottom (stone/scorpion but also morays, rays, some sharks) they can pump oxygen to the brain by special flaps on the top of the head called spiracles.
- CROWN OF THORN
A starfish that eats coral polyps. It has sharp spines that contain a toxin called saponis. It can eat 6 square meters of corals per year. The stomach secretes digestive enzymes to absorb nutrients from the liquefied coral tissue. It can move up to 20 meters per hour. Predators: triton’s trumpet shell fish, a species of puffer, two types of trigger fish and some predatory shrimp are known to eat them, but like all starfish they are masters at rejuvenating lost limbs, so unless the predator eats the whole thing, there’s a good chance that the COT will not die. Total predation of adult COTs is very rare. Big quantities of land fertilizers that reach the sea water may increase algae and this is the main food of the crown of thorns larvae.
Like all cephalopods patterns and colors are produced by different layers of cells stacked together. In one layer they have chromatophores: responsible for black brown orange red and yellow. They are sacs with pigments under the skin with muscles attacked to the sacs. Each chromatophore is controlled by the brain. In the second layer we find the iridophores: they reflect light to produce blue, green, gold and silver colors. In the third layer we find leucophores: they reflect the predominant wave length of light in the environment, often responsible for white color. In some cuttlefish, especially deeply and nightly species, we find also photophores, they are light organs that produce bioluminescence by chemical reactions. Also the texture of the skin can be changed using special sets of muscles. By contracting rings of muscles, the center of the ring is forced up to form a spike or a flap in the skin.
- DAMSEL FISH
It defends vigorously their territory from intrusions and may bite even divers. The most territorial male is the one that has more chances to mate. A couple take care of their babies. It eats algae, plankton and/or invertebrates. Some damselfish will strip the polyps from whip corals in order to lay their eggs where they are more exposed to currents. Later these whips will be colonized by other organisms like tunicates, sponges and hydroids.
- DECORATOR CRAB
A nocturnal crab which uses materials to hide and protect themselves from predators. It takes sedentary organisms such as algae or sponge and sticks them on it’s body for camouflage. The shell has many small hooks which act like Velcro. Sometimes they use stinging anemone or hydroids for a better defense.
- ELEGANT SQUAT LOBSTER
The female is bigger than the male. It lives in association with a crinoid in which it gets protections and ideal support for it’s feeding as they both eat plankton. It matches the color of it’s host. Usually it can be found in a couple.
- FANG BLENNY
All species have 2 large, curved canine teeth on the lower jaw and some species have even venomous fangs which are used for defense. Some species feeds attacking a fish and eating pieces of their fins or scales. If a predator sucks up the fang blenny it will bite his attacker and most of the times it can get free. The black line Cardinal fish mimic the blue striped fangblenny and the short head fangblenny. (example of bateism mimicry)
They have a single opening as mouth and anus on the ventral surface. Most reef species have rudimentary sensory organs in the form of pseudo tentacles on their head. Many species have eyes spots in detection of light. They eat small invertebrates or dead animals. (They are an example of mullerian mimicry and are probably toxic like nudibranchs. Some species can swim in an undulating fashion (like a magic carpet) if disturbed. Many are nocturnal, hiding under loose coral or sand during the day.
In the larvae stage it has the typical shape of a normal fish, with fins and eyes on each side of the body. Weeks later muscles, skin, blood vessels, bones shift into the flattened shape. Also one eye migrates to one side next to the other and the swimbladder disappear. Camouflage is the best defensive strategy. It has shaped cells in the skin, the chromatophores, connected to the nerves, which change body color within a second to match the surrounding.
- FROG FISH
Its hunting technique includes a perfect camouflage to pass unobserved by its prey and the use of a lure to attract it. This lure, on the top of its dorsal fin, if damaged or eaten can be regenerated. The mouth can expand 12 times its normal size. It doesn’t have a swim bladder so it uses pectoral fins to walk or jet propulsion to swim further. Can change color but slowly usually over days or a few weeks, to match their surroundings. It eats fishes, crustaceans and even other frogfish and has one of the fastest recorded strikes in the animal kingdom: 6 milliseconds.
- GARDEN EEL
It may form large colonies of over 1000 on sand plains and slopes where it extends the body out of their burrows to pick plankton from the current. It digs a burrow with its tail and it uses a special mucous to help cement the sand grains of the burrow to keep the tunnel intact.
- GOBY AND PARTNER SHRIMP
They meet with a chemical cue when young and they stay together for all their life. The shrimp are almost blind so they need a sentinel like the partner goby. They both have advantages in living together: the shrimp works to keep the burrow open and clean and the goby signals if there are any threats by touching the shrimp with its tail. If needed they will go quickly inside their house together.
They are colonial animals similar to soft corals but supported by an elastic skeleton that supports polyps. Often called sea fans, they are not reef builders like the massive corals. The fan is a colony which occurs singly, but if the conditions allow there can be many fans in a small area. Usually they occur deeper because they do not tolerate wave action and they are usually on sections of reef exposed to strong currents. They grow perpendicular to the reef wall to maximize their exposure to the current rather than orientating themselves towards the sun.
It doesn’t have a swim bladder and so will sink if they stop swimming. The dominant male keeps a harem. A female may become male. The unusual thing is that the male my also reverse its own sex if challenged by a more dominant male.
- HARD CORAL
They are reef building colonies of individual polyps that usually live in waters between 21 to 29 degrees (70f to 85f). They can survive for a while in different temperatures (18-36 degree). Every polyp secretes calcium carbonate extracted from the water to form an external skeleton that provides protection. The coral gets the color from the algae (zooxanthellae) that lives in the coral polyp tissues. This algae helps the polyp to produce calcium carbonate but also and most importantly provides nutrition to the polyps through the act of photosynthesis. This is why corals need clear, shallow water.
Warmer water and long periods of calm surface conditions can cause polyps to eject the algae (bleaching). If the warm conditions persist the polyps will die and the reef will quickly become covered in fast growing algae which doesn’t support the fish diversity of a typical healthy reef.Mostly polyps open at night (when the algae is not producing) and the polyps eat plankton. The corals we typically see while diving receive up to 80% of their energy requirements from the symbiotic algae while deeper corals (no sun light) are much more predatory. The coral start as a larvae that swim to the surface of the ocean and remains there for days or weeks. If nobody eat it while is in the free water, it fall back to the floor and it will attach to an hard surface. The larvae become a polyp and the coral begin to grow dividing itself in half and making exact genetic copies of itself. As more as the polyps are added, the colony develops. When it becomes mature it will begins reproducing (spawning).
Some species of coral such as brain coral produce eggs and sperm at the same time. Other corals produce only eggs or only sperm. Mass coral spawning events in some areas occur only one particular night per year!
- HALIMEDA ALGAE
It’s a fast growing reef building green macroalgae composed by calcified green segments made of calcium carbonate (The same composition of the hard coral but without the polyps!).
It’s a plum shaped colonial animal (cnidarian) related to jellyfish, corals, fans, and anemones. It’s carnivorous and feeds on plankton. They use toxic organs (nematocistos) like jellyfish and anemones, to feed and for defense. Main predators are nudibranchs.
- BUMPHEAD PARROT FISH
Often it swims in groups, but sometimes is solitary. It eats up to 5 tons of coral per year and produces up to 90 kg of sand per year. Like all parrotfish it is primarily a herbivore which feeds on algae which would otherwise smother the corals but eats and digests the polyps of corals as well. They defecate a fine coral sand away from the reef. The larger males have been observed using their oversized heads as battering rams in fighting over territory or mating.
The Cymothoid Isopod is a parasite. It attaches itself to the skin of a fish. When it finds a good host they stay permanently. It produces anticoagulants like vampire bats and it sucks the fish blood. It can cause damage, also serious, to its host ranging from: slow growth rate, tissues damage, anemia, and death. Smaller species of isopods infect the mouths of fish, killing the tongue by severing the artery and then actually replacing the victim’s tongue with its own body. The host fish is able to continue a normal life with an isopod for a tongue.
It is native of indopacific and it is of the family of the scorpaenidae but unlike the scorpion fish it actively hunts for its prey as opposed to lying in wait. Life span is 15 years. Usually it is hovering just above the bottom or hiding in crevices during the day and becomes active at night. It eats small fishes, crustaceans and even other lionfish. Predators are: moray eels, big groupers, sharks.
Volitans Lionfish is an invasive species introduced in the 90’s in the Caribbean, where it has no natural predators. It has devastated the number of other fishes there.
The spines are hollow like hypodermic needles and deliver an extremely painful sting. Juveniles have been seen to mimic feather stars for defense but adults will rely on their more developed toxin alone.
- MANTIS SHRIMP
There are two groups of mantis shrimps: the smashers and the speakers.
The smasher has large powerful claw arms used for breaking shells. It hunts often in the open during the day.
The spearer has long back folding appendages for grasping preys. It hunts from the entrance of their burrow.
The movement of the arms has been timed at 23m per second. This is so fast that can cause cavitation bubbles (such as a boat propeller does). The cavitation bubble effectively creates a second smash after the initial strike. The sudden water movement alone can stun or kill prey. The smashing mantis is known as one of the strongest marine animal (it can breakthrough an aquarium glass).
It has the most complex eyes in the animal kingdom: the eyes move independently, has perfect perception of depth and has a wide perception. It is able to see the ultraviolet light and it detects polarized light. This means that it can more easily recognize transparent or semitransparent prey or see predators such as barracudas which have shimmering scales. The human eye has 3 types of color receptors while the mantis has 16!
- MIMIC FILEFISH/SADDLEBACK TOBY
They have a very similar skin pattern. The mimic file fish uses the mimic strategy to have more chance to survive. By mimic king a saddleback toby, (which is a toxic puffer fish), it will have less probability to be eaten. The main difference between these two fishes is the dorsal fin that is long on the file fish while shorter and closer to the tail on the saddleback toby.
It can reach 1 m long. It lives in shallow marine areas or at the surface of open water. They are capable of jumping out of the water and can reach speeds of up to 60 km per hour. The sharp beak it can inflict deep puncture wounds, often breaking off inside the victim. This has happened to some divers and fishermen during the night when the needlefish were attracted and excited by the lights.
There are more than 2000 species with 4 sub orders.
a) Branched gill on the back (typical of chromodoris).
b) Sets of paired gills structures on the back
c) Hidden gills (typical of phillidia).
d) Cerata: numerous respiratory organs on the back (typical of flabellina).
They have primitives eyes like sea stars which can see changes to light. They have a pair of sensory organs called rhinophores that most of them can retract and some have also two head tentacles. Some of them have stinging nematocysts in the cerata, harvested from cnidarian preys that they use against predators, while others collect toxic or disgusting substances from the food they eat and so become toxic or distasteful to potential predators. They communicate with a slime trail that they leave behind (like garden slugs). They can live up to one year. They may eat sponges, hydroids, tunicates, algae, corals, fish eggs, dead fishes and even other nudibranchs! Main predators are some fishes, sea spiders, turtles and sea stars.
It has 3 hearts, two which pump blood through the gills, the third pumps blood to the rest of the body. It has blue blood. 2 thirds of the octopus neurons reside in the arms, not in the head. It is very smart, it uses tools such us shells and coconut to hide from predators. Sometimes it collects trinkets from the sea to make his own “garden”. While the female protects the eggs she stops eating and, when the new octopuses born, the mother’s body begin a cellular suicide and she dies.
The teeth of the parrotfish have fused into powerful beaks that can rasp the algae from the skeletons of the dead coral. In the process it eats also calcium carbonate, the coral structure. It has a specialized alimentary tract, without a true stomach, that extracts food, leaving the remain returning back to the sea as sand.
During their life most of the parrots go through a series of changes that alter their colors, markings and body shape. Juvenile phase – initial phase – terminal phase. Most of the species in the initial phase are female while in the terminal phase are always male.
- PEGASUS SEA MOUTH
It has a bony external armor. It walks with the pectoral fins.
- PYGMY BOBTAIL SQUID
Very small, it has a big brain. Within the body it has bioluminescent bacteria that it uses to camouflage, mimicking the moonlight at night and to eliminate its shadow. It also controls the brightness of the glow caused by bioluminescent bacteria. During the day it is buried in the sand. If it is found or disturbed, it turns white and it leaves a cloud of ink to escape.
- PYGMY SEAHORSES
There are 7 pygmy species known, They can have different coloration even if they are of the same species. It has a tubular mouth, fused jaws, and feeds on microscopic zooplankton which it sucks up using its snout. The Bargibanti and the Denise pygmy lives its entire life on a single gorgonian and usually it’s range within the fan is only approximately 20 cm across. The couple usually sleeps together. Like all seahorses, the female transfers the eggs to the male and the male becomes ‘pregnant’. The male gives birth to live baby seahorses which drift in the current hoping to find a suitable host. Dark or black at first, the babies will slowly change colour and take on the appearance of the host gorgonian- warts and all.
The white and the brown are different in that they are usually found amongst Halimeda algae or in association with sponges and hydroids. These pygmies may actively move around unlike their cousins which stay on the same fan. Whites and browns are sometimes seen together.
It has venomous dorsal, ventral and anal spines, which can inflict extremely painful wounds. It is named after rabbits because it’s a vegetarian and has a big appetite.
- RIBBON EEL
It changes sex depending on the age unlike the other moray eels which have a single sex. In the juvenile state it’s a male with a black body with a yellow line running down its back. When sexually mature, it turns blue with a yellow stripe while the terminal phase is female and completely yellow. (actually someone have seen a big ribbon eel still black…). The life span is 20 years.
- ROBUST SEA CUCUMBER
It is very similar to a yellow nudibranch. It uses the mimic strategy to resemble a toxic or bad tasting nudibranch.
- RED BULB ANEMONE
The fluorescent color absorbs high energy, short wave length light, such as ultraviolet light and remits it as a lower energy, longer wave length visible color that has high reflectance value. That’s why even in deep water you see the anemone still red. The convection color just reflects the light.
- SCORPION FISH
All its fins are venomous but the tail. It has skin flaps and tassels to augment the ability to change colors for better camouflage. Predators are sharks and groupers.It can change colour within seconds to mimic what it is sitting on. It will normally give warning displays when approached closely.
- SEA KRAIT
It has descended from the krait family which includes Asian cobras, it is very venomous.The venom is reserved for the prey which is almost exclusively moray eels.The sea krait is more adapted to the land than the true sea snake. Sea snakes have lost the belly scales which allows it to crawl on land so they live their entire lives at sea and give birth to live young. All snakes/kraits breathe air and drinks fresh water. It rests and nests on rocky headlands and beaches. The female grows bigger than the male. Sometimes, in remote Indonesian reefs, where the snakes hunt all together, they are followed by goat fishes and trevallies for a cooperative hunting.
- SEA CUCUMBER
It is part of the echinoderms family which includes starfish. It feeds on algae, minute aquatic animals, waste, material which it eats with its 8 to 30 tube feet (tentacles) surrounding its mouth. When threatened it can contract its muscles to expel some organs. After it will quickly regenerate it. Predators are crabs, some fish, turtles, sea stars.Certain species of sea cucumbers are eaten in Asia and now in some places they are quite rare.
Some sea cucumber such as the black spotted sea cucumber mimics nudibranch when in the juvenile stage.
Easily confused as being seaweed, it is more closely related to the flowering plants of land. It produces flowers and seeds. It is one of the most productive ecosystems of the world. It provides shelter and food to an incredible diverse community of animals, from invertebrates to large fish, juvenile fishes, crustaceans, turtles, marine mammals and birds. 1m square of sea grass produces 10 litres of oxygen every day. Their roots trap and stabilize the sediment that help to improve water clarity and quality, important to maintain the right conditions for the coral life. Some turtles can eat up to 2kg per day of sea grass.
- SEA PENS
It is a kind of soft coral that lives in colonies and feed on plankton. They position themselves where they can have free current flow, ensuring a steady flow of food. For defense they may force water out of the colony so they can retract into their peduncle. Predators are some kinds of nudibranchs and sea stars. They can live for 100 years!
- SEA STARS
They are normally nocturnal animals, part of the echinoderm family. It has no brain and no blood, instead it has filtered salt water inside the body. There are many different species that can have from 5 to 50 arms. Each arm can be regenerated. It has tube feet underneath the arms to walk and a small eyespot at the end of each arm which senses light. It has a hard bony skeleton for protection. The mouth is in the middle, from which the stomach emerges when eating and the anus is on the top. Different species may feed on mollusks such as clams, oysters, sand dollars, mussels, sea urchins.
Predators are other sea stars, bottom sharks, anemones.
- SOFT CORALS
The soft coral is composed of a rubbery, jelly like material with supportive skeletal spicules. It has a vascular system that allows it to inflate to feed when current runs and deflate during slack periods. Not all but some species of soft coral need light to survive because they have zooxanthellae (algae which make the photosynthesis to get energy).
- SOLAR POWERED NUDIBRANCH
This big nudibranch eats leather corals. It ingests the zooxanthellae algae from the coral tissue. This passes through the digestive system and continues to work by photosynthesis as it is stored on the surface of the nudibranch body and cerata. The animal receives energy indirectly from this photosynthesis.
- SPANISH DANCER
It can be enormous, up to 46 cm long. It swims moving its body reminding to a Spanish dancer skirt. It eats sponges and jellyfish. Like many nudibranchs, they are toxic or bad-tasting. Even the eggs have high concentration of toxins so they are protected also before they hatch. The egg casings are commonly seen here and may contain 3-4 million eggs. They are normally seen only at night and either bury or hide amongst corals during the day.
It is a venomous fish with eyes on the top of the head and an up facing mouth. Usually it buries itself in the sand and looks for prays. It has 2 venomous spines just above the pectoral fins. Some kind of stargazers can also cause electric shocks. Electrogenesis may be used for: electrolocation, self defense, electrocommunication and sometimes for stunning a pray.
It has the most deadly fish venom known. The Protein-based neurotoxin affects the brain and central nervous system is located in 13 spines along the dorsal fin and is thermolabile. It lives on the bottom, sometimes completely buried in the sand, waiting for prey to swim to close to its mouth. They change their skin from time to time, so they can be seen pink/purple or covered in algae.
- STRIPED EEL CATFISH
Its anterior spines of the dorsal and pectoral fins contain venom that can inflict painful wounds or even be fatal. The striped eel catfish is the only catfish found on the coral reef. This kind has evolved the ampullae of Lorenzini (same as the sharks) that are electro-sensory organs that detect electromagnetic fields product by all living animals. Juveniles form a dense-ball shaped school of up to 100 fishes while the adults are solitary or live in a small group. During the day it hides under ledges. The adult grow up to 30 cm and has 4 pair of barbels. It eats crustaceans, mollusks, worms, fishes
- SWEETLIPS FISH
Related to the snappers, it is known in many regions as grunts because of a “grunting” sound produced by rubbing flat teeth plates together. They are nocturnal predators of molluscs. Juveniles are often brilliantly coloured and swim erratically, potentially to mimic wriggling flatworms/nudibranchs.
- THREE SPOT DAMSELFISH
It is cousin of the anemonefish and juveniles can be seen among the tentacles of the anemone to get protection. When juvenile it is immune to the stinging tentacles, while when grows it will loose the immunity.
- TITAN TRIGGER FISH
Active in the day time, it feeds by turning over rocks, stirring up sand and biting pieces of hard coral. Triggers have a spine, like dorsal fin that it uses as defense against predators or to lock itself firmly inside the crevices. It may be aggressive to other creatures that pass through its territory. They have been known to attack humans when defending their nest, often in a depression in the sand. The eggs are pinkish and look like candy floss. The dorsal pine may be erected as a show of intimidation. With eyes on the side of their heads they often need to swim on an angle to view potential threats. It eats mollusks, sea urchins, crustaceans, tube worms, corals.
- TRUMPET FISH
It can camouflage well with certain corals like whip corals. Sometimes it uses a hunting technique called shadowing: it swims above or behind a big vegetarian, non-dangerous fish (ex. angel fish), to get closer to the prey without being seen.
The difference from hawksbill and green turtle is that the first has a pronounced beak and a “dirty” shell encrusted with algae while the second has a rounder head and normally a cleaner, beautifully patterned shell. The hawksbill turtle lives only in tropical waters. It eats mollusks, algae, crustaceans, sea urchins, stars, jellyfish and sponges. Green turtle mostly eats sea grass and algae. Males and females may be identified by the tail: the male has a longer tail than the female, that helps to grab the female during mating. Young turtles are unable to dive well and they spend their early years floating amongst sea plants near the surface. Green and Hawksbill may spend up to 25 years in the open ocean feeding on jellyfish and carrion before returning to the area where they were born. They never stop growing and may live to over 100 years old. Predators are sharks, big fish, octopuses, birds. Most turtles are eaten by predators before they reach the relative security of the open ocean.
- JAW FISH
It resides in burrows in the sand and it creates a tunnel. It broods its eggs in its mouth until the little fishes born and it protects them in this way even later. It eats plankton and small organisms floating past.
- WHIP CORAL GOBY
Usually it lives in pairs in association with whip and wire corals. It responds to chemical signals released from the coral reef it inhabits. As it lives the whole life in one of this corals, it keeps this environment cleaned from toxic algae. It strips living polyps from the host whip in order to lay its eggs. This bare area later gets colonized by other corals and may in fact kill the whip.
- ZANZIBAR SHRIMP
It lives only in the wire corals. The female is twice the size of the male. It feed on parasites, algae and plankton.