Head to head
Rainbow Trout vs Brown Trout
These are the two trout that anglers all over the world have come to know, because both have been carried far outside their native ranges and stocked into cool rivers and lakes on six continents. But they come from opposite sides of the world and different branches of the salmon family, and they look and behave differently once you know what to look for.
| Rainbow Trout | Brown Trout | |
|---|---|---|
| Native range | Pacific North America and northeastern Asia | Europe, western Asia, North Africa |
| Family branch | Pacific salmon genus (Oncorhynchus) | Atlantic salmon genus (Salmo) |
| Side markings | Broad pink to red stripe; no coloured spots | Red and orange spots with pale halos |
| Tail | Covered in small black spots | Few or no spots |
| Spawning season | Spring | Autumn |
| Temperament | Less wary; takes a fly or lure readily | Very wary and selective; hard to catch |
| Sea-run form | Steelhead | Sea trout |
| As an introduced fish | Widely stocked worldwide | Widely stocked; invasive in some regions, displacing native fish |
Rainbow Trout vs Brown Trout: common questions
What is the quickest way to tell a rainbow from a brown trout?
Two features do it almost every time. First, the tail: a rainbow trout has small black spots peppered right across the tail fin, while a brown trout's tail is nearly clean, with few or no spots. Second, the side spots: a brown trout has scattered red and orange spots along its flanks, each one surrounded by a pale bluish or whitish ring, which a rainbow trout never has. Backing those up, the rainbow usually shows a broad pink or reddish stripe down the side and along the gill cover, and the brown has an overall warm golden-brown cast. Colour alone can be misleading in stocked or lake fish, so rely on the tail and the haloed spots.
Which is harder to catch?
The brown trout, by reputation and by most anglers' experience. Brown trout, especially wild ones and large ones, are wary, spook easily, feed selectively, and often do most of their feeding at dusk, at night, or in difficult light, and a big brown that has survived several seasons has effectively been trained by every angler who failed to catch it. Rainbow trout tend to be bolder, more willing to chase a moving lure or rise to a fly in open water, and quicker to recolonise after disturbance, which is one reason they are the workhorse of put-and-take stocked fisheries. This is a generalisation, though; a heavily fished rainbow in a clear spring creek can be just as maddening.
Can rainbow and brown trout live in the same river, and do they interbreed?
They frequently share the same rivers, particularly where both have been stocked, and they partition the habitat to some degree, with browns often holding the prime lies under banks and logs and rainbows using faster, more open water. They do not naturally hybridise in any meaningful way, because they are only distantly related, in different genera, and they spawn in different seasons, spring for the rainbow and autumn for the brown. Where they overlap as introduced fish, the interaction is competitive rather than genetic, and in some places the introduction of one or both has driven down native trout, char, or, in the Southern Hemisphere, native galaxiid fish.