Beetles

actually they're cockroaches my friend

I looked at the sign, they are sun beetles

@felis silvestris they’re certainly not sun beetles

I'm afraid these are very definitely cockroaches. They look like Periplaneta americana. If the tank was labelled as sun beetles then these are probably escaped livefoods that have got in there at some point!

Sun beetles look like very different: Sun beetle (Pachnoda marginata) aggregation - ZooChat

@Maguari You are probably right lol