Editing Trout (section)

==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 auxiliary device for [[oxygen]] uptake, relying solely on their [[gills]].

There are many species, and even more populations, that are isolated from each other and morphologically different. However, since many of these distinct populations show no significant genetic differences, what may appear to be a large number of species is considered a much smaller number of distinct species by most [[Ichthyology|ichthyologists]]. The trout found in the eastern [[United States]] are a good example of this. The [[brook trout]], the [[aurora trout]], and the (extinct) [[silver trout]] all have physical characteristics and colorations that distinguish them, yet [[gene]]tic analysis shows that they are one species, ''Salvelinus fontinalis''.

[[Lake trout]] (''Salvelinus namaycush''), like brook trout, belong to the char genus. Lake trout inhabit many of the larger lakes in North America, and live much longer than [[rainbow trout]], which have an average maximum lifespan of seven years. Lake trout can live many decades, and can grow to more than {{convert|30|kg}}.