I have a 55 gallon tank running on a wet dry filter. I've got two occellaris clowns, two regular firefish, and a coral beauty. My parameters are all fine. Ammonia - 0, Nitrite - 0, Nitrate - 20.
Out of the blue today, I noticed that one of my firefish is being really aggressive towards the other one. These two have been in the tank together for 2 to 3 months. Never had any issues with them. They slept in the same place, and hung out in the tank at the same place. Now the one chases the other to the opposite side of the tank.
I've never really heard to much about firefish aggression. Maybe they're learning from my clowns. They've been doing their dominance thing for months now... Should I worry about this, or is it like the clownfish thing?