freshwater
Brown Trout
Salmo trutta
Elongated, slender body with a large head. Coloration is typically olive-brown on the back, transitioning to golden-yellow on the sides and white on the belly. It is distinguished by dark spots surrounded by pale halos and often features prominent red or orange spots along its flanks.
- Habitat
- Prefer cold, well-oxygenated freshwater environments suc…
- Size & weight
- Typically 25 to 60 cm in length and weighing 1 to 5 kg.…
- Diet
- Carnivorous and opportunistic. Juveniles feed on aquatic…
Identified More freshwater →
Learn more about Brown Trout in the encyclopedia →Identify your own catch.
Get a report just like this from any photo, free.
Physical characteristics
Elongated, slender body with a large head. Coloration is typically olive-brown on the back, transitioning to golden-yellow on the sides and white on the belly. It is distinguished by dark spots surrounded by pale halos and often features prominent red or orange spots along its flanks.
Habitat & distribution
Prefer cold, well-oxygenated freshwater environments such as streams, rivers, and lakes. They are native to Europe and North Africa, but have been widely introduced globally to all continents except Antarctica.
Behavior
Highly territorial and often solitary, especially older individuals. They are primarily diurnal but can become more active at night in areas with high human activity. They often seek cover under banks, logs, or overhanging vegetation.
Diet
Carnivorous and opportunistic. Juveniles feed on aquatic insects and larvae, while adults primarily eat smaller fish, crustaceans, and occasionally terrestrial insects that fall into the water.
Reproduction
Iteroparous spawners that lay eggs in gravel nests called redds. Spawning typically occurs in late autumn or early winter in flowing water. Unlike most Pacific salmon, they can survive spawning to breed again in subsequent years.
Ecological role
Apex predator in many freshwater systems. They control populations of smaller fish and invertebrates, and are themselves prey for larger mammals and birds of prey.
Similar species
Rainbow Trout (Oncorhynchus mykiss), which has a pink lateral stripe and many small black spots on the tail; Atlantic Salmon (Salmo salar), which has fewer spots below the lateral line and a more forked tail.
Identification tips
Look for the characteristic red spots with light halos and the absence of spots on the tail fin. The adipose fin (the small fin between the dorsal fin and tail) often has a reddish tint.
Interesting facts
Brown trout are known for their high intelligence among fish species and their ability to become extremely wary of human presence. Some populations are anadromous, meaning they migrate to the sea to grow before returning to freshwater to spawn.