Christmas Island’s fish community is distinctive because the island is a meeting place for Indian and Pacific Ocean fish species – it’s one of the few locations in the world where Indian and Pacific Ocean fish swim side by side. Some of these species interbreed to produce hybrids. Christmas Island has more hybrid fish than anywhere else in the world, making it a marine hybridization zone of international significance. Around 575 species of fish have been identified from the island's waters and are mostly fish associated with coral reefs.

SURGEONFISH & UNICORNFISH
Surgeonfish are an important herbivore on the reef and are commonly seen grazing in shallow waters, often in schools. They are named for the scalpel-like blades at the base of their tail. These blades can inflict a serious wound if the fish is handled carelessly. Unicornfish are generally found in smaller groups or pairs and many species feed midwater on plankton.

TOADFISH & PUFFERS
These slow moving fish are able to puff themselves up into a ball. This puffing ability, along with their highly toxic flesh and skin, make them unpalatable to predators. They vary in size from 5 to 90 cm, are generally uncommon, occurring singly or in pairs.

DAMSELFISH
Damselfish are probably the most common shallow water fish found on coral reefs with over 300 species found worldwide. The group includes the most famous coral reef fish – the clownfish or anemonefish. There are three species of anemonefish at Christmas Island (among other damselfish species) and they can be seen living safely amongst the tentacles of their host anemone on the reef top and edge between five and 40 m. Damselfish range between 4 and 10cm in length.

HYBRIDS
At least 11 different hybrids have been recorded at Christmas Island. These hybrids are often a result of interbreeding between Indian and Pacific Ocean species. Usually one of the parent species is rare and unable to find a partner, forcing it to mate with the next closest species. On Christmas Island, species of surgeonfish, butterflyfish, angelfish, triggerfish, wrasse and toadfish have been know to produce hybrids. The hybrids are identified by their unique colour patterns, which are a mixture of the two parent species. Hybrids can be seen in the same locations as the parent species and often in the same social groups.

CODS & BASSLETS
This broad group includes small colourful basslets (15 cm) and large predators (up to 2.7 m). The basslets may form harems of one male and many females, or large schools. These vibrantly coloured fish (usually purples, reds and yellows) are abundant on the drop-offs, where they hover above the reef feeding on plankton. The cods and groupers (20-270 cm) are ambush predators that camouflage with the reef and engulf prey such as fish and crabs with their large mouths. They are often spotted or barred.

GOATFISH
These slender cigar-shaped fish are easily recognised by their two barbells (whiskers) situated under the chin. The sensitive barbels are used to sift through the sand and detect prey such as shrimps. Goatfish are commonly between 20 and 40 cm in size and they often have a distinct stripe or spot on the body.

ANGELFISH
These spectacularly coloured fish are highly prized by photographers. Ranging in size from five to 50 cm, they are among the most elaborately patterned fish in the world. Angelfish are distinguished from other fish by a noticeable spine on their lower cheek. The Cocos angelfish is found only at Christmas and Cocos Islands as is the endemic subspecies of the lemonpeel angelfish. Lemonpeel angelfish are common in the shallows at Christmas Island – identify the juveniles by the black spot with a blue margin which fades as they become adult.

MOORISH IDOL
The Moorish idol is a picturesque fish that looks like a butterflyfish but is in a family of its own. It has black, yellow and white vertical stripes with a trailing dorsal filament and is found in the same shallow coral reef habitat as butterflyfish. You may see it on its own, in pairs or in small schools. Look for juveniles sheltering amongst branching corals.

MORAY EELS
Thirty-four species of moray eels have been recorded at Christmas Island all of which come in a variety of colours, shapes and sizes. They are generally found hiding in and around hard corals and can often be seen whilst snorkelling or scuba diving. Some species have blunt teeth which are used for crushing crabs and molluscs while others have sharp, needle-like fangs used more for feeding on prey items such as fish, shrimp and octopus. Moray eels are not normally aggressive however the masked moray eel can be territorial and bite intruders if they come too close.

WRASSES
This is a diverse group that exhibit a range of sizes (5-230 cm), colours and diets. The majestic humphead maori wrasse is the largest member and uses its powerful jaws to crush shellfish or feed on crown-of-thorns starfish. One of the smallest members of this group is the blue and white striped cleaner wrasse, which feeds by eating parasites from other fish that visit the wrasse’s ’cleaning station’. Most wrasses form harems where the largest member of the social group is a brightly coloured male surrounded by dull coloured females.

BUTTERFLYFISH
These are one of the most beautiful groups of fish in the sea. Their posterlike colours and unique patterns make them easy to identify. Typically 8-15 cm in length, butterflyfish can be seen on shallow coral reefs, swimming in pairs and picking at food on the substrate. Some species feed exclusively on corals, while others have a broad diet.

TRIGGERFISH & LEATHERJACKETS
These two closely-related families are distinguished from other fish by the presence of a sturdy dorsal spine that they erect to help wedge themselves into holes when danger approaches. These fish have rough skins and some, such as the clown triggerfish, have vivid colour patterns.

PARROTFISH
Parrotfish are closely related to wrasses but can be distinguished by their fused teeth that look like a parrot’s beak. Usually 20 to 100 cm in length these fish are commonly seen in shallow water grazing on algae. Some species eat corals that they crush with their powerful jaws, returning sediment to the reef in the form of sand. Like wrasses, many parrotfish have a haremic social system with the largest fish being a brightly coloured male and the smaller fish are dull coloured females.