Green fish (not the real name)

They are the harmless and green version of the Sentinel and are fish-like NPC's that eat remains or food, they can be used as food because when killing them your capacity bar has a little charge.

While Vrylle201 was playing brutal.io he played in a server that had 3 players, and he saw a school of the green fishes that had uncountable green fishes, this can only be seen if only the server had 1-6 people on a server.