Fish breeding in aquariums

Breeding of aquarium fish

Breeding aquarium fish – often the main goal

To breed aquarium fish is not only desirable from a sustainable point of view, it is also fascinating and exciting.

Many fish species care for their brood and it’s really fun to observe how the parents protect and look after their offspring.

Breeding by accident

You can find offspring in your aquarium without you having planned it. Your fish just feel comfortable, the conditions are perfect and there are males and females present which like each other. But it may well be that the fry have only a slim chance of survival, and are considered as a treat for both their parents and the other aquarium dwellers. You can only save the fry when you separate the babies.

Either you catch the fry to rear them in a separate aquarium or you use a spawning box ( JBL BabyHome Oxygen , JBL BabyHome pro Air , JBL NBox ), which can be used for the offspring until the juveniles are too large to be eaten. For the rearing of the mini fish you then need the suitable food. For that a special feeding kit has been designed consisting of three tins which have been precisely adapted to the size of the fry ( JBL NovoBaby ).

For the fry the following food sorts are available:

JBL PRONOVO BEL FLAKES S
Main food flakes in size S for all aquarium fish from 3-10 cm
JBL PRONOVO BEL FLAKES BABY
Rearing food set for juveniles of viviparous aquarium fish
JBL PlanktonPur SMALL
Treats for small aquarium fish
from 10,70 £
More View product
JBL PRONOVO BEL GRANO BABY
Powdered food for juvenile fish in the aquarium
JBL PRONOVO BEL FLUID
Liquid rearing food for young egg-laying aquarium fish
JBL ArtemioSet
Complete breeding kit for live food
from 58,66 £
More View product

Focused breeding

If you specifically want to breed certain fish species, it is necessary to take the following parameters into account:

Male or female?

Do you really have males and females? Two females can also spawn, but the eggs don’t become fertilised.

Unfortunately, there are no general rules for distinguishing characteristics in male and female fish. The males are usually more colourful than the females, but there are exceptions to this. Example: guppies, Yucatan mollies, many gouramis.

Yucatan mollies, in front above the female and behind the courting male

In other live-bearing toothcarps, males and females are coloured the same, but the females are plumper and have an anal fin instead of a mating organ (gonopodium).

Male
Female

In many cichlids, the males are more beautifully coloured than the females. The exceptions to this include angelfish, discus and butterfly cichlids.

In the case of the purple cichlid (Pelvicachromis pulcher), both sexes are beautifully coloured, but the female is always plumper and smaller
In firemouth cichlids and some other species, the males are larger, but not necessarily more beautifully coloured
Discus pair
Also in the butterfly cichlid: BOTH sexes are beautifully coloured

Sometimes it’s easy to distinguish between the sexes with the cichlids from the East African lakes Malawi and Tanganyika and sometimes it is difficult. With juveniles it is always as good as impossible to recognise their gender. Only sometimes, when their colours develop, does a visible sex difference (sexual dimorphism) appear.

Some Malawi cichlids show a pronounced sexual dimorphism. In this species the males are yellow!
The sexes of shell dwellers are difficult or even impossible to distinguish
Only the males of the Tanganyika snail cichlid have a pronounced forehead hump
UW photo from Lake Malawi: The brown animals are females or not yet fully-coloured males

In Central American cichlids there is the formation of forehead humps in males.

Many gouramis have clearly visible colour differences between the sexes. These include pearl gouramis, dwarf gouramis, honey gouramis and a few more. In the others, the dorsal fins of the males are usually more extended than those of the females and the females have a fuller body shape.

With many juvenile fish, the sexes can only be distinguished when the animals have reached sexual maturity. Before then, they all look the same and the strongest males will change colour first! Suppressed males do not show a beautiful "male colouration” either, so that they are not fought by the highest-ranking male. Only when the highest-ranking male dies will the next male change colour.

Brood predator or brood carer?

Brood predator: Many tetras and barbels lay their eggs freely in the water or plants. Afterwards they are left to themselves and the later hatching fry is eaten. Here you either need to remove the parents or the eggs/fry from the aquarium.

Livebearers: As the name indicates, guppies, platties and other live-bearing tooth carps give birth to living young. You can put pregnant females into a spawning box ( JBL BabyHome Oxygen , JBL BabyHome pro Air ), where they give birth to their babies which are protected by a grid from the mother, who may regard the fry as food.

Brood carers: all cichlids, labyrinth fish and many other fish species lovingly care for their brood. This doesn’t always work the first time, but they learn and eventually they rear them, often even in the presence of other aquarium dwellers. You only need to make sure that they feed their fry. Fry hatching from eggs are significantly smaller than live born fry.

Food for fry

There are various sizes and an entire food range to choose from for the fry:

Freshly hatched, very small

JBL PRONOVO BEL FLUID
Liquid rearing food for young egg-laying aquarium fish
JBL PRONOVO BEL FLAKES BABY
Rearing food set for juveniles of viviparous aquarium fish
JBL ArtemioSet
Complete breeding kit for live food
from 58,66 £
More View product

Small to medium-sized fry

JBL PRONOVO BEL GRANO BABY
Powdered food for juvenile fish in the aquarium
JBL PlanktonPur SMALL
Treats for small aquarium fish
from 10,70 £
More View product
JBL ArtemioSet
Complete breeding kit for live food
from 58,66 £
More View product

Medium-sized to large fry

Now you also can grate your flake food to feed the parent animals.

JBL PlanktonPur SMALL
Treats for small aquarium fish
from 10,70 £
More View product
JBL PRONOVO BEL FLAKES S
Main food flakes in size S for all aquarium fish from 3-10 cm

Suitable aquarium equipment

Your fish have adapted to their habitat and their breeding is often also closely tied up with the habitat. Some cichlids and long-whiskered catfish lay their eggs in caves. If there is no cave available, the fish have a problem. Make sure you offer your cave breeders few breeding dens to choose from ( JBL Cocos Cava , JBL Ceramic spawning cave ). Some fish species spawn in rock crevices, and some on plant leaves or stones. Please check the spawning habits of your fish to adapt the aquarium decoration accordingly.

Discus fish, angel fish and other cichlids lay their eggs on vertical surfaces, no matter what they are. Because natural surfaces, such as wood and plants contain germs, experts prefer so-called spawning cones ( JBL DisCon ) which can be boiled or just disinfected.

Many cichlids from Lake Malawi and Lake Tanganyika, but also from waters of other continents, are mouthbrooders. The females put their eggs in their mouths after laying, along with some sperm from the male and thus brood the eggs in their mouths. After a gestation period they release their young from their mouths.

Dense planting areas help fish species which spawn freely into the water or in plants. Here the eggs are more or less safe from predators. Experts use grids above the bottom or glass marbles to protect the eggs from the parents.

Fish species that build foam nests are happy if you support their nest-building efforts by adding floating plants and if there is no or hardly any current in the area of the nest. These fish species include a large number of labyrinth fish (gouramis, some species of fighting fish and macropods).

The right water

Find out which water parameters are important for your fish. Sometimes there are differences between the ”normal“ keeping and ”breeding conditions“. Some fish species, for example, only spawn when the temperature drops slightly or the water flow increases. In nature this is often connected to the rainy season. As a rule most fish prefer a regular partial water change than any fíddling around with the GH, KH and pH. But this may change when breeding: here the right hardness and pH value can be decisive!

Read more about this at Water values .

Conductivity: you will find information about conductivity and breeding for some fish species. This concerns the electrical conductivity of your aquarium water. The more salt in the water, the more the water conducts electricity. However this doesn’t refer to the sea salt, but to any kind of salt, such as general hardness, carbonate hardness, but also phosphates, nitrates or sulphates. If a low conductivity of 80 µS/cm is indicated for your fish to be bred, experts do the following: They use a reverse osmosis unit to filter almost all the salts (95 %) out of the tap water. This way they produce ultra-soft water which is almost equivalent to distilled water. Then they add a mineral salt mix ( JBL Aquadur ) to precisely set the conductance they require. Larger partial water changes of about 50 % often have led to breeding successes too! It’s worth a try!

Current

Some fish species, such as loaches or barbels need a very strong current to get into the mood to breed. The normal waterflow of the water generated by the filter is by far not enough. With the help of flow pumps Pumps you can intensify the current in your aquarium to liven up the fish.

Food

Who wants sex with an empty stomach or when the meal was horrible? What applies to people is also true for fish. Nutrition also plays a significant role for the success of the breeding! You have probably researched the right food for your fish. To start a breeding attempt, variety and some treats need to be on the menu. Sometimes it is enough to feed natural plankton ( PlanktonPur ). With this a lot of breeding attempts have been successfully started. For herbivorous fish (plant eaters) supplementary feeding with salad, peas or cucumbers can be very beneficial. In any case it is important that plenty of food and variety is on offer.

Modifying aquarium filters

If fry are expected you need to insert the intake strainer of your external filter into a foam cartridge ( JBL ProFlow sf for u800,1100,2000 ) so that they can’t be sucked in by the filter. For smaller aquariums it is useful to directly use a “fry safe” filter, such as the JBL CristalProfi m greenline .

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