"Cephalic fins": The "horns" of manta rays and their relatives, sometimes called cephalic fins, are actually a modification of the anterior portion of the pectoral fin. Pelvic/Ventral fins: Found in pairs on each side ventrally below the pectoral fins, pelvic fins are homologous to the hindlimbs of tetrapods. They assist the fish in going up or down through the water, turning sharply, and stopping quickly. In gobies, the pelvic fins are often fused into a single sucker disk that can be used to attach to objects. Adipose fin: A soft, fleshy fin found on the back behind the dorsal fin and just in front of the caudal fin. It is absent in many fish families, but is found in Salmonidae, characins and catfishes. Its function has remained a mystery, and is frequently clipped off to mark hatchery-raised fish, though data from 2005 showed that trout with their adipose fin removed have an 8% higher tailbeat frequency. Additional research published in 2011 has suggested that the fin may be vital for the detection of and response to stimuli such as touch, sound and changes in pressure. Canadian researchers identified a neural network in the fin, indicating that it likely has a sensory function, but are still not sure exactly what the consequences of removing it are. Caudal keel: A lateral ridge, usually composed of scutes, on the caudal peduncle just in front of the tail fin. Found on some types of fast-swimming fish, it provides stability and support to the caudal fin, much like the keel of a ship. There may be a single paired keel, one on each side, or two pairs above and below. Finlets: Small fins generally between the dorsal and the caudal fins, but may also be between the anal fin and the caudal fin. In bichirs, there are only finlets on the dorsal surface and no dorsal fin. In some fish such as tuna or sauries, they are rayless, non-retractable, and found between the last dorsal or anal fin and the caudal fin. Internal organs Intestines As with other vertebrates, the intestines of fish consist of two segments, the small intestine and the large intestine. In most higher vertebrates, the small intestine is further divided into the duodenum and other parts. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine may be used instead of