Dorsal fin
Videos
A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the f
Dorsal fin of a shark
Most fish, like this large goldfish, have one dorsal fin.
Many catfish can lock their dorsal fin spines erect and secrete venom to discourage predators.
The great white shark's dorsal fin contains stabilizing dermal fibers that stiffen dynamically as it swims faster to control roll and yaw.
Fish fin
Videos
Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and lift, which help the fish swim. Apart from the tail or caudal fin, fish fins have no direct
Skeleton of a lingcod, a ray-finned fish
Lobe-finned fishes, like this coelacanth, have fins that are borne on a fleshy, lobe-like, scaly stalk extending from the body. Due to the high number of fins it possesses, the coelacanth has high manoeuvrability and can orient its body in almost any direction in the water.
Pectoral fin with fleshy lobe of Latimeria chalumnae (Citron / CC-BY-SA-3.0)
Skeleton of the pectoral girdle and fin of the extant coelacanth Latimeria chalumnae (Citron / CC-BY-SA-3.0)