Virtual Learning Center

Wildlife Wonders

Today is Rainbow Trout Day!

Rainbow trout are no different from other fish in that they live in water, use gills for breathing, have fins to help them swim and steer in the water, like most fish they have scales on their skin and they have a layer of mucus or slime that helps protects them from diseases.  Just like in a tree, you can tell the age of a fish by looking at the rings (annuli).  These rings are found in the scales.

Rainbow trout are native to the west coast of North America from southern Alaska to Mexico, but because they are such a popular fish they have been introduced to almost every state.  They usually live in cool water  (50-60oF).

Rainbow trout coloration varies with the size of the fish, their “habitat” and during the time they are spawning or releasing eggs. Stream dwellers and “spawners” usually show the darkest and most vivid colors.  They aren’t all seven colors of the rainbow (ROY G. BIV – red, orange, yellow, green, blue, indigo, violet), but they are pretty colorful.  Rainbow trout are torpedo-shaped, generally blue-green or yellow-green in color with small black spots on their back and fins, and they have a broad red or pink stripe along the middle of its side and silvery white on underside. 

Rainbow trout and steelhead are both classified as Salmon.  In fact they are the same species, but they are called different names because they have different lifestyles.  Rainbow trout spend their lives in freshwater (some go into brackish water, a mix of fresh and salt, but not saltwater).  Steelheads are “anadromous” they spend part of their lives, 2-3 years, in the ocean (saltwater) before returning to the rivers and streams (freshwater) where they were born and spending another 2-3 years.  Steelhead, like its name indicates, is silvery or brassy in color and are more streamlined in shape. 

The females dig out a depression in the stream and deposit the eggs, the male fertilizes them and they are covered up and remain there for 2-3 months before they hatch.  Newly hatched trout are called “fry”, and then they become “fingerlings” and finally adults.  They will feed on a variety of foods including insects, crustaceans and small fish.

In Connecticut, the state record for rainbow trout is 14 lbs. 10 oz.  They usually weigh about 8 lbs, 20 – 30 inches and live about 4-6 years.  The largest recorded rainbow trout was 11 years old and weighed 57 lbs.  How did they tell the age…by looking at the rings on their scales. 

Rainbow trout and steelhead are an important food source for humans, brown bears, birds of prey such as eagles, and other animals. 

Fish biologists are not sure why some fish stay in freshwater (rainbow trout) and others migrate to the ocean (anadromous steelheads).   Offspring (babies) of steelhead can become rainbow trout and offspring of rainbow trout can become steelheads. Icthyologists (people who study fish) aren’t sure of the reasons for them becoming rainbow trout or steelheads. It could depend on their “habitat” or it could be genetic…or a combination of both.  So if you become an icthyologist maybe you can discover the real reasons.

Fishing Fun :: Association of Fish & Wildlife Agencies

About the Author

Skip to content