Just via doing a quick search for "Sacramento Perch," they kind of look like Rock Bass, or maybe even a type of green sunfish. With mouths of that size, they probably need a good supply of minnow-type fish to really thrive.

I don't know what your winter temps get down to in the winter, but that would have to be compared to any kind of stated temperature limitations with Sacramento Perch.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."