A Discus (Symphysodon spp.) guarding its eggs
Fish breeding is a challenge that many aquarists find attractive. While some species reproduce freely in community tanks, most require special conditions, known as spawning triggers before they will breed. The majority of fish lay eggs, known as spawning and the juvenile fish that emerge are very small and need tiny live foods or their substitutes to survive. A fair number of popular aquarium fish are livebearers, and these fish produce small number of relatively large offspring, and these will usually take ground flake food straight away.
Fried fish & French fries (fish & chips)
The flesh of many fish are primarily valued as a source of food; there are many edible species of fish as well as other sea food.
Shellfish include shelled molluscs and crustaceans used as food. Shelled molluscs include the clam, mussel, oyster, winkle and scallop; some crustaceans are the shrimp, lobster, crayfish, and crab.
Eggs, called roe, of various species may be eaten; roe comes from fish and certain marine invertebrates, such as sea urchins and shrimp. In some cultures, roe is considered a delicacy, for example caviar from the sturgeon.
Squid and octopus are valued as food.

Oology, or oölogy is the branch of zoology that deals with the study of eggs, especially birds' eggs. It can also be applied to the hobby of collecting wild birds' eggs (which is now illegal in many jurisdictions). Oology includes the study of the breeding habits of birds, and the study of their nests. (The study of birds' nests is sometimes called caliology).
Birds' eggs are conveniently classified as marked or unmarked, according to the ground color. Birds which lay their eggs in holes in trees or in the ground almost always have white, unspotted eggs. Birds which build in trees generally have blue or greenish eggs, either spotted or unspotted, while birds that build in bushes, near the ground, are likely to lay speckled eggs.
Ukrainian Easter eggs
Egg decorating is the art or craft of decorating eggs. Any bird egg can be facilitated in this process, but most often the larger and stronger the eggshell is, the more favoured it will be by decorators.