Several years ago while helping to stock Atlantic Salmon fry with the CT DEP, I noticed how very light colored the salmon looked. I asked the biologist why they looked so pale, and would this light color be a negative factor in their ability to survive, being they stuck out like a sore thumb. He told me they were just lifted out of the tank on the truck and they took on the shade of the tank which was an off white color. When they were released into the stream they would head for the bottom and seek out cover in the gravel and within minutes change color and blend into there surroundings.
Over the years I've noticed the different colors that brook trout take on, while in the fall they are at their most brilliant colors, they also have various colors depending on the water they are caught in. It seems that in light sandy bottom streams they tend to be light in color, in clear gravel bottoms they tend to be somewhat darker in color, and in dark tannic stained water they can be almost black.
And in only two instances in the many years of brook trout fishing I have done, I have taken a very bright and bluish colored brook trout, one in CT and the other in brackish water on Cape Cod, MA.
A light colored brook trout from a light gravel bottom stream.
A brook trout taken in a dark tannic stained stream.
A brook trout as autumn nears
A bluish colored brook trout,taken in a CT stream in early Dec. One of only two I have ever taken that were colored as such.
Click on the image twice, and you can see the various colors of these beautiful fish.
This diverse color variation may be another way this wild jewel has been able to survive in meager habitats since the ice age.