- Elongated, torpedo-shaped body with a robust build.
- Flattened head with a slightly pointed snout.
- Forked tail with rounded lobes.
- Small, cycloid scales that are deeply embedded in the skin.
Coloration:
- Back and sides are typically brown, olive, or golden-brown with a greenish-yellow tint.
- Dark brown to black spots with pale halos cover the body, including the dorsal fin.
- Spots can vary in size, density, and distribution, depending on the subspecies and geographic location.
- The belly is usually pale yellow to white.
Fins:
- Dorsal fin is located in the middle of the back and has a slightly concave margin.
- Adipose fin is small and located behind the dorsal fin.
- Pelvic and anal fins are positioned close together, with the anal fin being slightly larger.
- Pectoral fins are rounded and located on the sides of the body, just behind the head.
Other Distinctive Features:
- Brown trout have prominent jaws, with the upper jaw extending slightly beyond the lower jaw.
- The mouth is equipped with sharp, pointed teeth, including canine-like teeth on the front of the upper jaw.
- During spawning season, male brown trout may develop a pronounced kype or hooked lower jaw.
It's worth noting that brown trout can exhibit variation in coloration and markings due to genetic diversity and adaptation to different habitats.