[ironspider]

Even once in a while, my two biggest baddest fish fight. They are both cobalt blue got at the same time from a breeder, are the same hue of blue and are both about the same size. Both are beautiful fish. While they usually control their own half of the tank (55gal 48') every once in a while they get together for a battle. They are the only ones that will lock lips and stay connected like that. Any other fighting in the tank consists of chasing. It's a very interesting show as they go on for about a couple minutes like that. Is this dominance behavior? Are they going to try to kill each other? I can't get a pick as they scatter when I get closer to take a pic.

 

[DJRansome]

Both the fighting and the chasing are aggression over dominance. Two males of the same species not fighting would be a surprise, this behavior is expected. Watch closely for early signs of illness.

 

[awanderingmoose]

So long as each one is controlling some portion of the tank, you're probably fine. When you have to worry is when one controls the entire space, and the other has no territory and no safe space to hide.

 

[ironspider]

Both the fighting and the chasing are aggression over dominance. Two males of the same species not fighting would be a surprise, this behavior is expected. Watch closely for early signs of illness.

The other two blues are a bit smaller and a bit darker, chased once in a while but nothing like this. None of the other fish in the tank do this.