IMO the biggest disadvantage of mashed or powdered foods are they tend to reduce the water quality faster than natural foods. So if you use artificial foods pay attention to maintain good water quality.
Typically first foods are very tiny for many fish fry. Correct Size is important to these newly hatched, swim up fish fry learning to eat. These first foods usually consist of incidental phytoplankton, rotifers, and likely various protozoans. The fry start eating smallest particles first. Protozoans are not usually listed as first foods IMO due to their delicate nature and quick digestibility and becoming unrecognizable in gut contents. Protozoans are usually more abundant in the water than other larger species of zooplankton. These food organisms range in size from common algae 20-200um, protozoans 30-300, rotifers 60-800um. Reference: 1 milliliter(mm) is 1000um (micrometers) and 25.4 mm or 25400um per inch.
Newly hatched brine shrimp are around 400-520um. 'Baby' nauplii of common cyclopoid pond/lake zooplankton size range is 150-500um depending on age.
Many places that specialize in growing smaller varieties of fish such as minnows use rotifers as first food to feed the fry mainly those of the rotifer genus Branchionus which range in size from 120 to 300um.
Last edited by Bill Cody; 01/21/16 05:31 PM.
