Salmonidae

Rainbow trout

Oncorhynchus mykiss

A pink ribbon running from head to tail

• Black
• Green
• Pink
• Silver
• Tropical
• Northern Hemisphere
• Regional distribution
• Freshwater fish
• Fusiform
• Compressed cross-section
• Large
• Tropical fish

Celebrated for its agility and vibrant iridescent plumage, the rainbow trout is an iconic cold-water salmonid indigenous to the pristine river drainages of the North Pacific. Its torpedo-shaped silhouette presents a deep olive-to-blue back thickly scattered with small, irregular black spots covering the torso, dorsal fin, and squared caudal fin. A broad, luminous horizontal stripe of crimson or vibrant magenta blushes along the lateral line from the operculum to the tail base, intensifying markedly during breeding seasons. Native to cold gravel streams, high-altitude lakes, and coastal rivers from eastern Siberia and Alaska down to northern Mexico, it thrives exclusively in clean, highly oxygenated waters below twenty degrees Celsius. Highly opportunistic, it positions itself near gravel riffles and boulders to intercept drifting aquatic insect nymphs, adult caddisflies, terrestrial beetles, and small forage fishes. Anadromous forms that mature in the open sea are known as steelhead, while resident river populations remain in freshwater streams where females excavate gravel redds for egg incubation. Maximum recorded total length attains one hundred and twenty centimetres.

Sources: NOAA Fisheries — Steelhead & Rainbow Trout, Oncorhynchus mykiss