I'm guessing that you are not feeding fish feed into the pond?'

While the channel cat does not look 'unhealthy,' it does look a little bit thin, and I'm wondering if you've ran out of forage fish to feed the catfish.

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."