The comet (Calloplesiops altivelis), also known as a marine betta, is a tropical reef fish living along the East African coast that can be seen in our Indian Ocean Gallery. The small white spots on its dark black-brown body serve as amazing camouflage in the shadows of our tropical reef display, but once you've noticed it, its beauty becomes unavoidable.

Its large fins can be expanded wide, forming an oval disc, expanding the comet to almost triple its apparent size. These dexterous fins, together with a single blue-rimmed eyespot on its dorsal fin, are incredibly useful - the comet has a host of strange tricks at its disposal.

Comets are nocturnal predators, leaving their hiding places at night in search of small fish and crustaceans. When it spots potential prey, the comet will swim sideways towards it with its fins flared. The dorsal fin eyespot will confuse its prey into thinking that the comet’s tail is its head and it will try to escape “behind” the comet, but will actually be swimming towards its mouth to be eaten.

Once prey is spotted, the comet quickly turns itself sideways to trick the prey into fleeing in the wrong direction.

If a comet is startled or pursued by a larger predator when hunting, it once again uses these fins to good effect. The comet will hide its head in a hole or crack, and by flaring its tail it can fool predators into thinking that it is a moray eel's head, specifically the guineafowl moray eel (Gymnothorax meleagris).

This comet sees two large fish approaching and quickly pretends to be a moray eel until it knows it is safe.

What do you think of this elusive little wonder? Plenty more underwater oddities, from big noses to undiscovered jellies, are waiting for your next visit.

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