Dinicthoid

The Dinicthoid (scientific name: Gargoylia macropisceae or "giant gargoyle fish") is a fish like creature that lives in Pandora's lakes and murky lowland drainages. It has a very thick armor that makes it stronger than other fish

Description
When hunting at night, the dinicthoid can pulse with bioluminescence to take on the appearance of a smaller, more docile creature to lure prey closer. Conversely, it can control its markings to appear even larger and fiercer.

Its head features two large, protruding red eyes that can see for long distances underwater in dim light. It also features a disconcertingly humanoid false face (used to befuddle or frighten would-be predators) that is created by folds at the top of the skull.

When stimulated by prey or predators, it can reach high speeds by gyrating its flexible sides, much like a manta ray. It also has two flipper fins extruding from either side just beyond the head that are used for propulsion and steering.