Yellow watchman goby aggression

[PR_nano]

Have a yellow watchman goby who has turned really aggressive towards other inhabitants. Tank is 20 gallon with a purple firefish, pink streaked wrasse and the yellow watchman. He's been chasing them out can't stand to see them. I moved a rock something ago when the purple firefish displayed a similar behavior and it seems to work. I felt bad at the time since all fish got to a corner and even the pistol shrimp hold onto the rock and I was worried about crushing him.

Wonder if I should try it again or are there any other options?

Maybe place some rubble in front of one of the cave exit to block his view.

 

[Quietman]

Mine would chase other fish away but not overly aggressive. Never noticed any biting or nipping. Just their normal behavior in protecting their den. If no biting/nipping I'd let it go but keep an eye out for escalations.

If biting/nipping, you can try rearranging. I had a pink streaked wrasse and firefish in a 37 gallon and other than I noted above there were all ideal tank mates. In a 20 gallon that YWG is likely to claim 1/2 to 2/3 of it as the 'chase away ' zone.

 

[PR_nano]

Thanks, I will keep an eye on it. I have notice more aggression lately but no damage. He definitely owns at least 1/2 of the tank and don't let the other fish get to the other half of the tank. Basically have them cornered. I need to glue some corals and will likely move some stuff around, frag/rubble and see if it helps.

 

[Mr. Mojo Rising]

The tank is too small for those fish. The watchman is just protecting his cave, it’s normal behaviour.

 

[PR_nano]

Yeah, I think at least the YWG had outgrown the tank and seems to be better suited for at least 30 gallon tank.