Firefish aggression?

[Pat_13]

I am a bit confused as to what is happening and hopefully someone can help. :confused:

I have had all my current livestock for 4+ months in the main tank as follow: 1 Mandarin, 1 algae blenney, 2 firefish, 2 O. clowns, 1 cleaner shrimp, 2 peppermint shrimp, 1 emerald crab, and cleaning crew (100+ snails & crabs).

I bought both firefish at the same time in a LFS as a pair and they were in the same tank. They have always swum together and slept together until now.

The day after I added a Hector’s goby, I noticed one of the firefish was not with the other swimming about as normal. He was hiding in a new spot (not seen in before) and not coming out to swim. That night they were not sleeping together, still in new spot. The next day I noticed that it was the larger of the firefish that was chasing the smaller until he would go hide in the new spot. The hector seems to be hanging out at the bottom doing just fine, peaceful not bothering anyone. Both firefish were out at feeding and both were seen eating, but shortly after the smaller was chased again back to the new spot. Do you have any idea what may be causing this aggression in the larger firefish? Should I wait a few days to see if it passes or remove ASAP? The smaller one does not appear to be damaged at all.

[just dave]

Firefish live in male/ female pairs as adults. When juvenile they may live in larger groups. It is possible that yours were still juveniles when purchased.

[jc1of2]

I agree. I have a pair red firefish for about 1 year. Until just recently one is picking on the other and they no longer sleep in the same hole anymore. I think they matured and are different sexes.

[zemuron114]

If they are different sexes wouldn't they be pairing? I can see same sexes fighting and then finding different homes.

mosr firefish will fight, unless there are maybe 5+ as a group. even then some will pair off and kill/harass the others.

[Sk8r]

They may take to separate areas of the tank and just chase when one ventures into the other's territory. The Hector's arrival was more or less chance, no likely connection. I have the same combo, and the firefish just don't get along.

[jc1of2]

Sorry, meant to say same sex. Its getting to the point that I have to catch one of them and move it to another tank. The picked on one is very thin, its afraid to come out and eat.

[Pat_13]

The picked on one is now coming out a lot more and is out most of the day now, BUT he has one large tear in his tail fin. I tried to catch one after a few days but they are way to fast and I don’t want to take out all the rock just to catch him but if it gets worst I will. They seem to keep to keep to opposite ends of the tank now. I think he tore him a him a new a$$ and they are now OK with their new territory?

Yes, I think the addition of the goby is just a coincidence.

[zemuron114]

thats good to hear. the tail will heal :)