Portrait of the very rare and shy Comet or Marine Betta (Calloplesiops altivelis). It can reach a maximum length of 20 cm.
The Comet Fish is naturally nocturnal and hides under rocky crevices and in holes during the day. At night it leaves its hiding place and swims along the reef in search of food. They have an imaginary eye that sits on the dorsal fin, as you can see in the picture below.
In case of danger, this fish sticks its head into a hole and exposes its tail end, so the predator sees the large imaginary eye that mimics the head of a moray eel.