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Bony Fish
Bony fish (from the superclass Osteichthyes) are the most diverse and abundant group of vertebrates (creatures with a spine) on the planet. They come in all shapes, sizes and colours, but all have a bony skeleton which supports flexible fins, allowing greater precision of movement and flexibility to that of cartilaginous fish.
We aim here to introduce this group to you, bringing your attention to those which we admire the most - if you want to read about a partcular breed in more detail use the menu. This section will continue to grow, so please bookmark this page and check back frequently.
Anemonefish (Amphiprioninae)
Anemonefish and clownfish are from the subfamily Amphiprioninae in the family Pomacentridae. There are twenty eight species all of which choose to live amongst the stinging tentacles of giant anemones, and several brightly coloured varieties can be seen around Koh Tao. Being immune to the stings themselves, they hide amongst the tentacles for protection, but they will also act to defend the single anemone they live with. They also have mutually beneficial feeding habits.
Triggerfish (Balistidae)
There are several species of triggerfish varying from 30cm to 75cm in length. Named after the trigger (spine) located on its head which is used to indicate its mood as a warning to other creatures in the vicinity. In Koh Tao, you are most likely to see the titan triggerfish, though we do have sightings of other breeds such as the yellow margin triggerfish and clown triggerfish. Titan triggerfish can be aggressive when defending their nests, and the powerful jaws they use to crush the shell fish and corals they feed on can deliver a serious bite - it pays to know how to act if you should accidentally enter its territory.
Lionfish (Pterois volitans)
Lionfish are patterned like its name suggests and has numerous venomous spines all over its body. These spines are used while catching prey such as other fish and shrimps by stunning the pray with the venom and then consuming it; this is mainly done at night. They are rarely seen in Koh Tao, but have been spotted at Japanese Gardens and Chumphon Pinnacle.
Longfin Bannerfish (Heniochus acuminatus)
These unusual looking fish are black and white striped, which are used to interrupt the fish’s body form to confuse predators. They have a distinctive long tapering dorsal filament which lends the fish its name, and can grow to 25cm in length. The fish predates on zooplankton and bottom-living invertebrates.
Great Barracuda (Sphyraena barracuda)
Great Barracuda can reach up to 2m in length and are fast moving predators, with a stream-line body and powerful tail. They have extremely sharp, pointy teeth to catch prey, and they are aggressive hunters. They can often be seen during night dives when they hunt smaller fish by the light of divers' torches.
Cleaner Wrasse (Labroides dimidiatus)
Cleaner wrasse are small fish with a distinctive black band that lives are devoted to grooming other fish, turtles and even divers. They remove dead skin and parasites from other marine organisms; this is an example of mutual symbiosis, where the relationship benefits both parties. It's particularly interesting to see a cleaning station; normally a part of the reef where fish queue up to be cleaned by the wrasse - it's a bit like a drive-through car wash. Cleaner wrasse are just as eager to remove dead skin from divers, who tend generally to be less impressed with their services - it can sting a bit.
Yellow Boxfish (Ostracion cubicus)
As the name suggests, this is a box-shaped fish, and when juvenile (only a few centimetres in size), bright yellow in colour. Adults grow to a maximum length of 45cm. This fish has hexagonal bony plates rather than scales making it extemely tough, and despite the cutesy appearance, they are highly poisonous. The boxfish feeds on algae and tiny inverebrates.
Pufferfish (Diodontidae)
Pufferfish of the family Diodontidae come in over a 120 varieties, several of which can be seen around Koh Tao growing up to 45 cm in length. They are generally shy and reclusive, but they have several defence mechanisms, amongst which is the ability to puff up to several times their natural size making them look like a much larger more offensive fish; many also have spines which extend outwards all over their bodies when they are puffed up. They are chiefly nocturnal - a common site on night dives, and they feed on crustaceans and molluscs.
Where will I see them?
Everywhere! Submerge anywhere around Koh Tao and you'll see a plethora of bony fish from a bewildering variety of breeds.
