Yolk fry [also known sac fry, fish larvae (singular fish larva)] is the fry of fish between hatching and complete absorption of the yolk sac. That means a yolk sac bearing fish fry is known yolk fry or sac fry
Yolk sac
A sac (bag or pouch) like membranous extension of the gut containing nutritive materials (yolk) found in the larvae of bony fishes and the embryos of reptiles, birds and primitive mammals. It is situated at the ventral side of sac