You may be already be doing a lot constructive things, and may not need to change anything.

It may be helpful to keep a written log of the catch numbers and weights, by date, so you can analyze things more and make more calculated decisions. Our memories tend to be lacking when needed data.

I would also explore implementing a feed program. This can be done by hand, and does not require an automated feeder.

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."