It is an aggressive fish and is usually kept one male per tank.

Perhaps, and more likely, he was a particularly aggressive fish.

They can be kept with other large, less aggressive fish, or paired with their own kind.

The aggressive fish is an angler's dream come true.

They are aggressive fish and will try to eat anything you attempt to keep with them, so they are best kept on their own.

They are a somewhat aggressive fish, and may bully other fish in community tanks.

It should also not be kept with larger, aggressive fish that will eat them.

I'm not totally convinced that is would stop a very aggressive fish from finding a way through if it made up its mind to do so.

Pike are big aggressive fish found all around the world.

This seems to help protect them from some other more aggressive fish.