I put in fathead minnows last fall when my pond was pretty muddy, brand new, and about 6' deep.
This spring the water had cleared (thanks to Rainman) it's deeper, but not yet full, and absolutely full of FHM. They really multiply fast. I think I put in 10 pounds (1 acre pond)
Rex added some more this spring, I don't think you can have too many.
Jeff

9 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (going away), SMB, and HSB (only one seen in 5 yrs) Restocked HSB (2020) Have seen one of these.
I think that's about all I should put in my little pond.
Otter attack in 2023