6 Fish breeding strategies
To become a skilled aquarist, one should know the various techniques to breed fishes. While some fishes readily spawn in aquariums, it is very difficult to persuade some fishes to breed while in captivity. Hence, along with the strategies, natural environment should be recreated that stimulates spawning. Fishes use six basic breeding strategies. These are classified depending on how the eggs are laid/deposited and fertilized. Read on to be aware of the fish breeding strategies.
1. Egg scatterers
As the name goes, fish belonging to this species scatter the eggs in the aquarium. This category of fish spawns in pairs or in groups. They lay large number of eggs. The non-adhesive or adhesive eggs fall on plants, side of objects, on the gravel of the aquarium or floats on the surface. Egg mortality rate is quite high in this type of species. They use java moss as the spawning medium. Many parent fish in this category tend to eat the fry themselves. Hence it is better to separate the fry from the parent once the eggs are laid. Fry can also be separated even once they are born. Fishes that belong to egg scattering category are danios, tetras, barbs and silver dollars.
2. Egg depositors
Fish belonging to this category lay their eggs on a substrate such as wood, plants, or tank glass. The number of eggs laid by this category is far less than the egg scatterers. Among the egg depositors, there are two types - those that care for their young and those who do not. The fishes that care for the fry deposit eggs in cave, pit or an enclosure to clean and protect their eggs. The eggs of this category are larger than the eggs laid by egg scatterers. Discus and Angel are types of fishes under this category who care for their eggs. Rainbow fish and Killifish are egg scatterers that do not guard their eggs.
3. Live bearers
The fry of live bearers are hatched out of the mother fish. Eggs are not laid by live bearers. The male injects their sperm directly into the females using modified anal fin. The eggs develop inside the female's body. It normally takes around thirty two days for the fry to develop. The live bearer females are ready to breed immediately after they hatch a batch of fry. These are prolific and are the easiest species of fish to breed.
No specific environment is required to breed live bearers. However, protection must be provided to the fry, once they are born. There are two types under this category - Ovoviviparous and Viviparous. Ovoviviparous type of fish hatches eggs from within while Viviparous nourishes the young through an umbilical-like cord. Platies, Halfbeaks, Mosquito fish, Swordtails, Guppies are some of the types of fish under this category.
4. Nest builders
This category of fish builds a kind of nest to lay eggs. This is made of saliva and plant debris. The tank for nest builders should not have water current that could disturb the nest. The tank can have fine leafed floating plants with gravel or sand. Bettas and Gouramis are two species that make nests at the surface of the water to lay eggs. Fishes mate at the surface and then the female drops her eggs. These species lays less number of eggs. Subsequently, the male fish carries the eggs in its mouth to the nest for protection. The male fish looks after the fry and tends the nest in case of nest builders. They protect the nest from other fish and keep any other eggs falling on the nest. Male fish give protection to the fry in the nest until they become good swimmers.
5. Mouth brooders
These species carry the eggs in their mouth. With mouth brooders, the female receives the sperm from the male and fertilization takes place in the female's mouth. The eggs remain in the mouth for around three to four weeks. She does not eat during this time and becomes thin and weak.
In the other type of mouth breeders, the females lay the eggs on substrate and protect the eggs until they hatch. Upon egg hatching she carries the fry in her mouth until they become bigger. In some types, there are male fishes that carry their offspring in their mouth. No special environment is required to breed this species. Examples of mouth brooders are Catfish, Cichlids etc.
6. Egg-buriers
These species lay the eggs in the mud. They dwell only in those waters that dry up during certain time of the year. The parents of this species mature quickly and lay eggs before the water dries up. Rains stimulate the hatching of the eggs and remain dormant until such time. Killifish is one of type of fish that belongs to this category. Peat moss substrate is required to breed this type of species. Peat moss can be removed and stored in a plastic bag for weeks to months after spawning. The stored peat should be immersed in water to initiate egg hatching.
