Reef Fish Aggression Caught on Tape


While rummaging through old photos and videos in order to perform a long overdue backup of our data, we stumbled upon some really old footage showing a trio of blue green reef Chromis (Chromis viridis) displaying to each other aggressively. The three fish can be seen flaring their fins, presenting their sides in order to appear larger, nipping at each others’ fins, and even bumping their mouths together during the elaborate display. Normally these fish are sold as community fish that do well in large groups. Unfortunately, this information isn’t always correct. In the wild, Chromis do congregate in large masses above coral heads, but in the confined spaces of the aquarium their tempers can easily flare. This often leads to large groups of fish dwindling down to just a few individuals in the average saltwater aquarium.

Toward the end of the clip, a lonely damselfish also attempts to get into the mix, trying to assert a little of its dominance. Damsels are known to be very aggressive, so it’s no surprise that it got involved in the scuffle. Unfortunately for the little yellow tailed blue terror, it is quickly bullied into submission after its own brief display. The attacking chromis then proceeds to nip at its caudal and pectoral fins until it flees the invisible wrestling ring.

We also wanted to take a minute to apologize for the poor quality of the video. This clip is very old and was taken with a point-and-shoot camera. Fortunately, we still get to see a majority of the action


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