I didn't know they did that! I heard of someone who kept a Panaque (large pleco) in a display tank in an aquarium shop. It killed a piranha and a red-tailed catfish (large predator). It now lives in a tank on its own. This is not as surprising as it sounds - the panaque eats wood and plant material, so it has powerful spoon-shaped teeth, and it also has cheek spines. The three species live together in the wild, so the pleco probably recognised its natural enemies, and decided to get them out of its territory.
Keeping a collection of fish is always much, much harder than what it says in the books. They will chase each other, eat each other, damage plants, compete for food and grow enormous. Of course, they would do all that in the wild, but it isn't so convenient in a tank or pond.
Keeping a collection of fish is always much, much harder than what it says in the books. They will chase each other, eat each other, damage plants, compete for food and grow enormous. Of course, they would do all that in the wild, but it isn't so convenient in a tank or pond.