Fish reproduce in many different ways, depending on the species. Watching fish reproduce is one of the most fascinating things about aquaristics because there are so many different forms of reproduction in fish.
There are two main forms of reproduction in fish: egg-laying fish (ovuliparous, often called oviparous by abuse of language) and ovoviviparous (also called viviparous, by abuse of language).
How many eggs can a fish lay?
The number of eggs laid by a female fish varies according to its species and its size, it can go from a hundred eggs, that is to say the number of eggs laid by the viviparous fish, up to several millions, the sunfish being the record holder with more than 300 million eggs in one laying.
Their ways of laying eggs are very varied: some species dig nests, others cover their eggs, and still others prepare a bed of algae to protect their eggs.
The 2 different types of fish
The term viviparous means that the young are born already formed. For most of them, we even talk about ovoviviparous because the embryos remain in their egg, within their mother’s incubator pouch, until they are born.
The eggs are thus fertilized in the reproductive organs of the female by the intermediary of the gonapod of the male. The female incubates the eggs in a pocket annexed to its genital apparatus: the incubator pocket. One sees then a dark spot in front of the anal orifice.
The fry are thus born formed one by one. To avoid that they are eaten at birth by other fish, it is advised to place the female in a nesting box before hatching.
These are fish that lay and fertilize their eggs in open water, often within plants. Each species has its own preferences in terms of vegetation. The courtship is also specific to each species.
Fish that are ready to lay their eggs can usually be identified by their brighter colors and courtship.
How do you know if a fish egg is fertilized?
This is called external fertilization, which means that fertilization takes place in the marine environment, outside the two bodies of the fish. If after a few days, the eggs show a small black spot on their surface, it means that the fertilization is successful.
Can we eat the fish eggs?
Fish eggs are very nutritious and rich in micro-nutrients! However, their nutritional profile varies greatly depending on the method of production and the variety of fish from which they come. Tarama, for its part, is a relatively rich product with more than 300 kcal per 100g.
It contains an interesting quantity of polyunsaturated fatty acids, phosphorus and vitamin D. Caviar is a little less rich in calories but just as rich in fatty acids essential to health, vitamin D and phosphorus. Lumpfish eggs, on the other hand, are much lower in calories with less than 120 kcal per 100g.
Indeed, they contain less fat, but also less protein! Consumed in moderation and as part of a varied diet, fish eggs are therefore beneficial to the health of the body and its normal functioning.
How to preserve fish eggs?
Fish eggs are relatively fragile and do not keep for very long. They should be stored in the refrigerator in their original hermetically sealed box. Once opened, tarama must be stored in the refrigerator and consumed within 3 to 4 days to preserve its taste and texture.
Caviar, on the other hand, does not keep well and should be consumed within 24 hours after opening. Finally, lumpfish eggs can be kept a little longer, about 7 to 10 days in the refrigerator.