Infusoria / green water

'Infusoria' is a hobby name for mixed microscopic pond life (protozoans such as paramecia, rotifers, microalgae, bacteria), about 20-300 microns, grown in water with decaying plant matter. Green water is mostly microalgae (phytoplankton) grown with light and nutrients.

For: Newly hatched, very small fry (e.g. killifish, rainbowfish, tetras) too small for baby brine shrimp.

How to feed: Feed small amounts several times a day (fry need 3-5 small meals daily), for roughly the first couple of weeks, then switch to baby brine shrimp once fry are big enough. Avoid adding much culture water.

Careful: Cultures crash suddenly; an over-rich culture blooms with bacteria and loses oxygen. A crashed green-water tank must have dead algae siphoned out at once or its decay can use up oxygen and kill all the fry. Wild-collected material can bring in disease or pests.

Examples you may see in shops: Infusoria culture (home-made from aquarium water and vegetable matter, or paramecium starter), Green water (microalgae). Not endorsements.