Knowledge of trout species is important because different species have unique behaviors, habitat preferences, and life cycles, which can significantly impact fishing techniques, conservation efforts, and the health of the ecosystem. Identifying a specific trout species allows for a more targeted approach to manage and interact with them.

For better accuracy, I broke trout characteristics down by species:

Steelhead (ocean trout)

• Migratory fish
• Silvery, brassy, steely blue, emerald green, or olive. Dark spots above and below the lateral line, on the head, sides, and fins. Pink iridescent stripe down the sides.
• Multiple spawning cycles; swim upstream in freshwater to reproduce
• Best time: Dawn and dusk are prime times
• Lower natural fat content, lighter, milder flavor

• Diet: Aquatic and terrestrial invertebrates and small fish. Young feed on zooplankton
• Males develop a distinctive curve and hook in their lower jaw called a kite

Rainbow

• Purely freshwater fish
• Native to cold water tributaries throughout Asia and North America
• Diet: Insects, crustaceans, and small fish
• No taxonomic distinction from steelhead trout. Torpedo-shaped fish with a pink or red stripe, dark spots, blue-green or olive-green backs, silvery sides and a white underside.  Spineless fins with rays
• Best time: Early morning and late afternoon are consistently good times to catch rainbow trout, with the best feeding activity often occurring during low light conditions. 
• Mild taste and delicate texture. Often described as tasting slightly nutty

Brook

• Western North America, South America, Europe, Asia, Africa, and New Zealand
• Found in shallow streams as well as deep lakes and in the ocean as well.
• Dense, irregular patterning on its back. Color ranges from a light silvery blue to dark green with various shades of red, yellow, or off-white spotting
• Diet: Young eat plankton, mayfly and damselfly larvae, water beetles, snails, and worms. Adults eat insects, small invertebrates, minnows, and small fish. Larger eat fish, shrimp, salamanders, frogs, mice, eels, and small snakes 
• Spawn in the fall
• Best time: Early morning and late evening are the most productive times, but they can be active throughout the day in cooler water temperatures. 
• Slightly sweet flavor, light and delicate meat

Brown

• Every continent except Antarctica
• Higher tolerance for warm water
• Diet: mayflies, caddisflies, stoneflies, midges, scuds, sowbugs, crayfish, freshwater shrimp, daddy long legs, aphids, and ants
• Brown on their back and sides that fades to a yellow or cream-colored belly
• Spawn in the fall; certain populations spawn as late as mid-winter
• Best time: Similar to rainbow trout, early morning and late evening are prime times, but brown trout can also be active during the day, especially in deeper water. 
• Often considered gamier and less prized

Cutthroat

• Western regions of North America
• Distinct species although cohabitation and hybridization occur.
• Coastal populations breed in Feb. and March, inland populations, April and May.
• Diet: Benthic macroinvertebrates, aquatic insects, earthworms, grasshoppers, young salmon, sticklebacks, and other small fish
• Fewer, larger spots; characteristics are less distinct and more varied
• Best time: Early morning and late afternoon are best, with potential for good midday fishing in colder water conditions. 
• Taste similar to rainbow trout, but slightly stronger in flavor

Lake

• Found in deep, cold lakes, but also in rivers entering or exiting such lakes
• Ranges from shades of gray to olive-green. Their bodies are densely covered in pale spots, which do not change significantly during spawning season.
• Diet: Youth eat plankton, insects, and small invertebrates. Adults eat alewives, smelt, sculpin, and chubs 
• Best time: Overcast days or periods with less sunlight 
• Meat is greasy and fatty

Bull

• Distributed throughout North America
• Entire lives spent in freshwater environments
• Heads are uncommonly longer, broader, and flatter than other species
• Diet: Youth eat land and aquatic insects and Benthic forage fishes like sculpins. Adults eat trout, salmon, whitefish, and sculpins, mayflies and stoneflies
• Best time: Late summer, early Fall
• Meat is mildly oily, but with a pleasant flavor
• Considered “Vulnerable” by the International Union for Conservation of Nature

Regardless of species, trout are cold-blooded, so their activity is highly dependent on water temperature. Generally, water between 50-60 degrees provides optimal feeding conditions. 

Ideal water levels should not be too high or low. It is best to seek water with a slight current change; for instance, near the edges of current breaks where moderately deep and shallow water meet. The water should be slightly tea-colored, allowing for good visibility, but still providing cover for the trout. 

Like anything, success must be earned. A good angler will be able to identify habits and characteristics of different trout species, understand local fishing areas, and weather conditions. Putting everything together takes time and practice.