My initial thought is this is a coincidence... HSB are prone to a tighter tolerance of water parameters than many species. They are very intolerant of low DO. If it's not angling stress, I'd have to say it's a water quality issue.
What's current water temp?
Maybe shutting aeration down about 8am and leave it off during daytime, start again about an hour or 2 after dark in the Hot times during summer. possible heat stress.

Last edited by Snipe; 06/25/22 02:04 PM.