Emerald catfish

Timid by nature, the emerald catfish is a sociable species that spends a good deal of its time rummaging in river bottoms searching for food.

For that reason it’s recommended that aquarium keepers use only sand or very fine gravel to keep it from hurting its barbels.

Like a number of other catfish, the emerald catfish is capable of intestinal breathing. Its modified intestines allow it, when it feels the need, to come up to the surface, where it can “swallow” a little air. Once in its intestines, that air passes through the intestinal wall and enters the bloodstream. In this way, the fish can survive in environments that are very oxygen-poor.