I caught a Flathead Catfish on Lake Murray in Oklahoma over Labor day weekend. Are they normally green and black when they are this small?

I haven’t caught a bunch of them but they all seem to have different coloring, I assumed it must be the water they come from-

Yellow cat is a loose description. I have seen them black as well as green depending on the water as Steve mentioned.

That is precisely the color they should be at that stage of life.

Plus #1.

i think the clarity of the water body as well as structure makes all the difference in the color variance in the world

They can range from green to yellow, to black & even grayish. They usually turn yellow after being out of the water for awhile (as to the big ones). They can have spots or big freckle patches up to what looks like splotches. There can be many different reasons for their color to their splotches also.

I usually refer to them as two main varieties- PJ (Plain Jane) or Op (short for Opelousas), meaning spotted. In my years, as to the ones I have caught, it seems that the ones that do not have spots or splotches (PJ), seem to be less muscular, and more slender. And the spotted ones seem to huskier, more muscular, and stockier. It might be more akin to one that works out in a gym (exercises), and the other one does not. Who can say for sure?

Babies

I have also noticed from fishing different rivers and water while living in KS years ago, they tend to color to the environment some. Sandy flat river fish seemed to be lighter than some of the smaller water, and lake fish we caught?
Natures camo?

Stay safe everyone!
Ken