The freshwater habitats may be seen to be of many kinds. Fishes found in mountain torrents, Arctic lakes, tropical lakes, temperate streams, and tropical rivers will all differ from each …
The swim bladder of fishes follows the same developmental pattern as the lungs of land vertebrates. There is no doubt that the two structures have the same historical origin in …
Ray, any of the cartilaginous fishes of the order Batoidei, related to sharks and placed with them in the class Chondrichthyes. Rays are distinguished from sharks by a flattened, …
Two pairs of fins correspond to arms (pectoral fins) and legs (pelvic, or ventral, fins). There are also several unpaired, or median, fins—dorsal (back), caudal (tail), and anal (belly). Fish …
Most species of piranha never grow larger than 60 cm (2 feet) long. Colors vary from silvery with orange undersides to almost completely black. These common fishes have deep bodies, saw …
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