Starry Blenny Aggression

kfries · Nov 6, 2025

Does anyone have any advice for reducing aggression from a starry blenny when adding new tank mates? I have tried twice to add a diamond goby, and it is very aggressive towards them. It has killed two. I tried to use an acclimation container that I made, but after a day, it escaped. I have not added fish for many months and I am looking to add, yet again, a diamond goby and a pair of Mandarins.

Dread Pirate Dave · Nov 6, 2025

kfries said:
Does anyone have any advice for reducing aggression from a starry blenny when adding new tank mates? I have tried twice to add a diamond goby, and it is very aggressive towards them. It has killed two. I tried to use an acclimation container that I made, but after a day, it escaped. I have not added fish for many months and I am looking to add, yet again, a diamond goby and a pair of Mandarins.

What size tank do you have? With a smaller tank I would expect the same outcome as your previous attempts with similar shaped fish. (gobies especially)

Putting the blenny in you sump, if you have one, for a period of time and then reintroducing him back may help. Some use acclimation boxes to do the same but neither of these approaches are guaranteed to work.

BryanM · Nov 6, 2025

OP looks to have a 100g tank, and I'd think it would generally be fine - But since you've already tried twice, I would think the starry blenny is just not in to another fish in the tank that looks similar, and I don't think that is going to change.

I have a lawnmower blenny, a larger tank, and my wife also wants to add something similar, and I told her the same thing, we can try, but it might not work out, and she decided against it.

kfries · Nov 11, 2025

Thanks for the info. I have a 100g display. I may set up my 20G AIO and put the Blenny in there for a few weeks to let any new fish settle. I am going ot have to plan this out pretty well so as not to disrupt the tank too much.
On another note, that dang blenny bites me when I put my hand in there sometimes. My clowns used to be the aggressors; now this rascal has taken over.