Seems my betta bottle (1 gallon pickle jar, of all things) just had a daphnia breakout. The betta seems to like snacking on them, just checking on any problems beyond spoiling his appetite.
Well, he's going on a 7-day fast from food, to both get rid of excess bio stuff, and let him reduce the population. He should be getting a 10g in January, so as long as his current environment stays stable (75% water changes weekly), should be ok until then.
Years ago we used to buy daphnia frozen, along with blood worms and brine shrimp. Those three, along with a decent quality flake food were staples for my fish at one time. All fish, especially small mouthed fish love daphnia.
Len