Plankton is any organism that rides the currents of the ocean. It can include anything as large as a jellyfish to something as small as a bacteria. Microalgae is a microcopic orgamism such as some single celled algae (DT's). A macroplankton would be something like a fish fry or jellyfish.

Zooplankton are animals. Phytoplankton are plants. I feed DT's (micro/phytoplankton), zooplex, baby brine shrimp, and frozen daphnia. I bought some Fritz invert bouquet today and will start using it. I also plan on start using cyclop-eeze. This will hopefully replace the daphnia, zooplex, and baby brine that I am currently using.

Hope this helps,
Gary