c. virginalis Gila trout, Oncorhynchus gilae Rainbow trout, Oncorhynchus mykiss Kamchatkan rainbow trout, Oncorhynchus mykiss mykiss Columbia River redband trout, Oncorhynchus mykiss gairdneri Coastal rainbow trout (steelhead), Oncorhynchus mykiss irideus Beardslee trout, Oncorhynchus mykiss irideus var. beardsleei Great Basin redband trout, Oncorhynchus mykiss newberrii Golden trout, Oncorhynchus mykiss aguabonita Kern River rainbow trout, Oncorhynchus mykiss aguabonita var. gilberti Sacramento golden trout, Oncorhynchus mykiss aguabonita var. stonei Little Kern golden trout, Oncorhynchus mykiss aguabonita var. whitei Kamloops rainbow trout, Oncorhynchus mykiss kamloops Baja California rainbow trout, Nelson's trout, or San Pedro Martir trout, Oncorhynchus mykiss nelsoni Eagle Lake trout, Oncorhynchus mykiss aquilarum McCloud River redband trout, Oncorhynchus mykiss stonei Sheepheaven Creek redband trout Mexican golden trout, Oncorhynchus chrysogaster Genus Salvelinus, five of the 52 extant species Brook trout, Salvelinus fontinalis Aurora trout, S. f. timagamiensis Bull trout, Salvelinus confluentus Dolly Varden trout, Salvelinus malma Lake trout, Salvelinus namaycush Silver trout, † Salvelinus agassizi (extinct) Hybrids Tiger trout, Salmo trutta X Salvelinus fontinalis (infertile) Speckled Lake (Splake) trout, Salvelinus namaycush X Salvelinus fontinalis (fertile) Fish from other families Pseudaphritidae Genus Pseudaphritis Sand trout, Pseudaphritis urvillii Sciaenidae Genus Cynoscion Spotted sea-trout, Cynoscion nebulosus Anatomy Trout that live in different environments can have dramatically different colorations and patterns. Mostly, these colors and patterns form as camouflage, based on the surroundings, and will change as the fish moves to different habitats. Trout in, or newly returned from the sea, can look very silvery, while the same fish living in a small stream or in an alpine lake could have pronounced markings and more vivid coloration; it is also possible that in some species, this signifies that they are ready to mate. In general, trout that are about to breed have extremely intense coloration and can look like an entirely different fish outside of spawning season. It is virtually impossible to define a particular color pattern as belonging to a specific breed; however, in general, wild fish are claimed to have more vivid colors and patterns. Trout have fins entirely without spines, and all of them have a small adipose fin along the back, near the tail. The pelvic fins sit well back on the body, on each side of the anus. The swim bladder is connected to the esophagus, allowing for gulping or rapid expulsion of air, a condition known as physostome. Unlike many other physostome fish, trout do not use their bladder as an