Siamese fighting fish are as beautiful and as brilliantly colorful as any other tropical fish, but this isn't the reason they were first domesticated by us humans. As their name implies, Siamese fighting fish can be rather pugnacious. Males will engage other males in violent and turbulent clashes that can involve severe fin nipping, or worse.
We humans originally domesticated these fish not for their looks, but to stage contests between them. Apparently, we like to see a good fight. Surprisingly, these fish also seem to enjoy watching a good fish fight, as scientists have recently discovered.
When two Siamese fighting fish attack each other in a laboratory aquarium, researchers noticed that the other males in the vicinity will stop to watch the fight very closely. Is this rubbernecking just idle curiosity? Apparently not.
As it turns out, bystanders that have witnessed a fight between two rivals are much less likely to challenge the winner of the fight than they are to challenge the loser. In other words, these fish are keeping score. By remembering, and avoiding, the winners of other fights, these rubbernecking fish can protect themselves from bodily harm.
This research is interesting because it hints at an unrecognized complexity in the social interactions of fish. While it's well known that certain mammals (including humans) and certain very social birds are natural born rubberneckers, it's hard to find this behavior in the lower animals. For the Siamese fighting fish though, rubbernecking is a matter of survival.