Fish breeders know the dilemma: Especially the now so popular nano fish like the guinea fowl danio (Danio margaritatus) or the dwarf danio (Danio erythromicron) spawn willingly and can actually be bred very well, but the larvae are tiny... much too tiny to feed on artemiauplia at the beginning. In this case, special fine rearing food for fish larvae is very useful, possibly you can even use liquid rearing food.
For fish that feed mainly on plants, a plant-based fine dust food is also a good change for the young fish. Small guppy and Endler guppy babies are also extremely grateful for a vegetable dust food, which is given in addition to another, protein-containing animal-based rearing food or as a supplement to artemia euplii, and respond with healthy development and vigorous growth.
Rearing foods should always be adapted to the diet of the fish: fish that eat predominantly animal food, such as fighting fish, need a predominantly meaty diet even as larvae. If you want to save yourself the effort of breeding Artemia, you should also use an appropriate animal-based rearing food for breeding bettas.
Omnivores also get a finely grained rearing food adapted to their needs: it should consist of animal and vegetable components in more or less equal parts.