Floating plant; has been growing in outdoor tubs. Probably some snails, definitely some filamentous algae, riccia, and bladderwort. Last two aren't necessarily undesirable, but bladderwort is carnivorous and you don't want it in your daphnia culture. Bonus: free bucket! I didn't keep count of how many plants are in the bucket but there are a lot of babies; I'm going to ballpark it at 20.