Killed my first round goby tonight

[tweedwolfscream]

The fused pelvic fin is a dead giveaway. Almost all fish have a pair of pelvic fins on the forward part of their underside, but on a round goby they're basically webbed into one, which looks almost like a suction cup facing down. There's also the black dot on the front dorsal fin. Those two things can differentiate a round goby from anything that looks similar.