Tetra a tall dorsal fin characterized by a short connection to the fish’s body. Additionally, tetras possess a long anal fin stretching from a position just posterior of the dorsal fin and ending on the ventral caudal peduncle, and a small, fleshy adipose fin located dorsally between the dorsal and caudal fins. This adipose fin represents the fourth unpaired fin on the fish (the four unpaired fins are the caudal fin, dorsal fin, anal fin, and adipose fin), lending to the name tetra, which is Greek for four. While this adipose fin is generally considered the distinguishing feature, some tetras (such
Houndfish ages. The houndfish also has a more stout, cylindrical body and a shorter head than other needlefishes. They have dark blue backs and silver-white sides and are plain white ventrally. A houndfish has a distinct keel on the caudal peduncle, and the caudal fin itself is deeply forked. Juvenile houndfish possess an elevated, black lobe on the posterior of their dorsal fins. The longest recorded houndfish was , and the largest recorded weight was . In the Indian and Pacific Oceans, houndfish are found in the Red Sea and from the coast of South Africa, east to French Polynesia, and