Fishes have single circulation which implies, they have a [[1]] heart.

Fishes have a two-chambered heart, which is a type of single circulatory system. The heart of fish consists of one atrium and one ventricle, and it pumps blood in a single loop through the gills and then to the rest of the body. The blood is oxygenated in the gills and then delivered to the body tissues. So, the correct statement would be "Fishes have a two-chambered heart."