I know you can get frozen daphnia...had good luck personally with that. There is also frozen plankton...also contains a lot of good things...but with all frozen food, high phosphates are a challenge. There is a thread on here (R2R) about an automatic brine shrimp feeding box, newly hatched brine shrimp ( when they are actually nutritious) are released and the scooters and mandarins learn fast where it is and eat at a station that way so you can observe them better for isdues as well.