Blackfin Cardinalfish

Found in high wave energy areas, sometimes inhabiting empty snail shells, in Thalassia testudinum - seagrass beds, also over cobbles, coarse rubble, and mangroves, of shallow, foreshores and tide-pools.
They feed nocturnally on benthic crustaceans, fish, and zooplankton

Males incubate their eggs inside their mouths, as the egg masses increase in size they can be found with wide open mouths where they shift the eggs around to aerate the egg masses.