Caviar - eggs of fish. A distinction is made between bottom (whitefish) and pelagic (herring, flounder) caviar. The shape of eggs in most fish is spherical, some are oval (hamsa), drop-shaped, cylindrical (gobies). The size of eggs in different species varies from a tenth of a millimeter (some herring, flounder) to 90 mm and more in sharks and rays.

Caviar - eggs hatched in water by females of fish, amphibians, mollusks, echinoderms, as well as some other animals. The number of eggs laid at one time varies widely: from a few pieces in the polar shark and a few dozen in some Arctic hornbills to 300 million in the moonfish. Groups of eggs bound together by mucus may take the form of clumps, ribbons, cords.

Eggs (eggs) develop in the paired ovaries of females, in fish they are called ovaries. Fertilization of eggs in most fish is external and occurs directly in the water, but there are exceptions. Internal fertilization reduces accidental loss of eggs and sperm. Fish that lay eggs are called egg-laying fish.

Eggs released into the water are of two main types:

Pelagic eggs float in the pelagic zone, both near the surface and in the water column of this zone. Pelagic eggs are laid, for example, by flounder, codfish, codfish, chekhon, Caspian-Volga herring, and sardines. The buoyancy of pelagic eggs is provided by the low density of eggs, the presence of fat droplets, enlarged and watered perivitelline space and shell outgrowths. It has very small eggs, low protein content and bright coloration.

Bottom eggs are deposited on the bottom. Bottom non-sticky eggs hatch on the ground, while bottom sticky eggs attach to pieces of soil (e.g., Murmansk herring, capelin), to rocks or shells (sturgeon, gobies, etc.), to aquatic plants (roach, carp, etc.). Some fish bury their eggs in the ground.

Female northern shrimp carry fertilized outer eggs on their abdominal legs (pleopods) after spawning.