Freshwater Aquarium Freshwater Aquarium fish Breedingfish Breeding

Sameer G ChebbiSameer G ChebbiDept. of ZoologyDept. of ZoologyIndustrial fish and fisheriesIndustrial fish and fisheriesKarnatak Science College, DharwadKarnatak Science College, Dharwad

Breeding aquarium fishes requires a good Breeding aquarium fishes requires a good amount of care and patience. amount of care and patience.

There is a remarkable difference in the There is a remarkable difference in the techniques involved in breeding the egg techniques involved in breeding the egg layers and live bearers. layers and live bearers.

Breeding fish in the aquarium comprises Breeding fish in the aquarium comprises of the following stepsof the following steps

1.1. Setting up of spawning tankSetting up of spawning tank

2.2. Selection of spawnersSelection of spawners

3.3. Conditioning the brood fishesConditioning the brood fishes

4.4. SpawningSpawning

5.5. Rearing the fryRearing the fry

1.1. Setting up of spawning tankSetting up of spawning tank Each fish has its own specifications Each fish has its own specifications

regarding physio-chemical and regarding physio-chemical and environmental factors related to environmental factors related to spawning. spawning.

In the spawning tank always try to In the spawning tank always try to provide an environment similar to one in provide an environment similar to one in its natural habitat.its natural habitat.

Care must be taken to control the Care must be taken to control the following following

1.1. TemperatureTemperature2.2. pHpH3.3. HardnessHardness4.4. Water column levelsWater column levels According to the requirement of According to the requirement of

individual fish. individual fish. Unless proper care is taken, the eggs or Unless proper care is taken, the eggs or

the fry have very little chance of the fry have very little chance of surviving.surviving.

Spawning grids or traps may be used in Spawning grids or traps may be used in the breeding tank in order to save the the breeding tank in order to save the eggs from being eaten by the parents.eggs from being eaten by the parents.

The place where the aquarium is kept is The place where the aquarium is kept is also important since some fishes like the also important since some fishes like the Dwarf Gourami need sunlight, while other Dwarf Gourami need sunlight, while other like the Neon or Cardinal Tetras prefers a like the Neon or Cardinal Tetras prefers a dark aquarium. dark aquarium.

Even the development of the embroys of Even the development of the embroys of Neon and Cardinal tetras are affected by Neon and Cardinal tetras are affected by harsh sunlight.harsh sunlight.

But, the general rule is to cut down the But, the general rule is to cut down the illumination to its minimum in case the illumination to its minimum in case the breeding fish is an egg eater.breeding fish is an egg eater.

Temperature also plays a very important Temperature also plays a very important role in spawning. role in spawning.

A few degrees rise or fall in temp. may A few degrees rise or fall in temp. may change a listless (lethargic) fish into a change a listless (lethargic) fish into a glowing one anxious (nervous) to breed.glowing one anxious (nervous) to breed.

Most of the Tetras prefer soft acidic water Most of the Tetras prefer soft acidic water while the live bearers are totally the while the live bearers are totally the opposite, preferring hard alkaline water.opposite, preferring hard alkaline water.

The choice of the breeding tank is also The choice of the breeding tank is also very important.very important.

Even if the fish is small and requires very Even if the fish is small and requires very little space, the rule is to use as large an little space, the rule is to use as large an aquarium as possible for the breeding aquarium as possible for the breeding purposes.purposes.

In a large tank, fluctuation or variation in In a large tank, fluctuation or variation in temp. caused by the heater is less temp. caused by the heater is less affected than in a small tankaffected than in a small tank

The aquarium may be thickly planted in The aquarium may be thickly planted in order to prevent the fish from exploring for order to prevent the fish from exploring for eggs after spawning is over.eggs after spawning is over.

Selection of spawnersSelection of spawners The next step regarding spawning of The next step regarding spawning of

aquarium fishes is the selection of aquarium fishes is the selection of spawners.spawners.

Always select fishes that are healthy, Always select fishes that are healthy, having the required/desired qualities or having the required/desired qualities or those equalling standards.those equalling standards.

Similar eliminate diseased fishes and Similar eliminate diseased fishes and those with visible anatomical or genetic those with visible anatomical or genetic deformities like tumours, deformed spinal deformities like tumours, deformed spinal cord etc., cord etc.,

To get best results, employ selective To get best results, employ selective breeding.breeding.

Select spawners from different sources to Select spawners from different sources to minimise in breeding.minimise in breeding.

In the case of live-bearers, the only way to In the case of live-bearers, the only way to avoid inbreeding is to separate the males avoid inbreeding is to separate the males from females, once the sex could be from females, once the sex could be distinguished. distinguished.

Conditioning the brood fishesConditioning the brood fishes Most of the spawners have to be Most of the spawners have to be

conditioned before spawning.conditioned before spawning. The male and female fishes are reared The male and female fishes are reared

separately for one or two weeks.separately for one or two weeks. During this period, the fish are fed on live During this period, the fish are fed on live

food available in its natural environment.food available in its natural environment. Fishes like the barbs and tetras are Fishes like the barbs and tetras are

usually conditioned on a diet of live food usually conditioned on a diet of live food like mosquito larvae, tubifex worms etc.like mosquito larvae, tubifex worms etc.

Some aquarists often provide a menu with Some aquarists often provide a menu with varying diets of live food each day.varying diets of live food each day.

Not all egg layers are to be conditioned Not all egg layers are to be conditioned separately.separately.

Some fishes like the Angel and Oscar Some fishes like the Angel and Oscar need to be kept together in a shoal or pair need to be kept together in a shoal or pair for a long time before breeding takes for a long time before breeding takes place.place.

In such cases the school may be fed on a In such cases the school may be fed on a varying diet of live foodvarying diet of live food

They are not to be separated once they They are not to be separated once they pair up for spawning.pair up for spawning.

Considering live-bearers, conditioning is Considering live-bearers, conditioning is not always necessary.not always necessary.

Hence before breeding fishes should be Hence before breeding fishes should be conditioning is required for better result.conditioning is required for better result.

Conditioning of fishes helps in success in Conditioning of fishes helps in success in breeding activity.breeding activity.

Different fishes having different Different fishes having different conditioning factor which is based on their conditioning factor which is based on their breeding behaviour.breeding behaviour.

SpawningSpawning The conditioned fishes are usually The conditioned fishes are usually

released into the breeding tank at dusk released into the breeding tank at dusk (evening).(evening).

In some cases, the females are released In some cases, the females are released atleast a day or two prior to the release of atleast a day or two prior to the release of the male.the male.

This is to familiarise the female with the This is to familiarise the female with the aquarium conditions and to minimise fear.aquarium conditions and to minimise fear.

Fishes are to be released in a school or in Fishes are to be released in a school or in pairs, depending on their spawning pairs, depending on their spawning behaviour.behaviour.

Fishes like the Danios are to be released Fishes like the Danios are to be released in schools with larger number of males.in schools with larger number of males.

Rearing of fryRearing of fry Rearing the fry is the most difficult part.Rearing the fry is the most difficult part. If the eggs and fry are not given proper If the eggs and fry are not given proper

care, all your effort will be in vain.care, all your effort will be in vain. The eggs are to be tendered properly The eggs are to be tendered properly

preventing them from fungal attack.preventing them from fungal attack. A few drops of methylene blue into the A few drops of methylene blue into the

tank will minimise the fungal attack.tank will minimise the fungal attack.

The eggs infected further fungal attack.The eggs infected further fungal attack. There is nothing more difficult than finding There is nothing more difficult than finding

the right food for the new born fishes.the right food for the new born fishes. The dietary requirement of the fries of The dietary requirement of the fries of

different aquarium fishes are given with different aquarium fishes are given with different live food and artificial food.different live food and artificial food.

Breeding techniques and devices involved Breeding techniques and devices involved in breeding differ according to spawning in breeding differ according to spawning behaviour of the fish.behaviour of the fish.

The spawning behaviour differ with each The spawning behaviour differ with each family.family.

Variation also present among members of Variation also present among members of the same family.the same family.

The egg layers can be classified into The egg layers can be classified into different categories depending upon their different categories depending upon their breeding habits.breeding habits.

1.1. Egg scattersEgg scatters

2.2. Egg depositorsEgg depositors

3.3. Mouth broodersMouth brooders

4.4. Bubble net buildersBubble net builders

5.5. Live bearsLive bears

Egg scattersEgg scatters Examples: Danios, gold fish, hatchet fish,Examples: Danios, gold fish, hatchet fish,

Glass fish, kissing gourami, tetras, flying Glass fish, kissing gourami, tetras, flying barb, barb etc., barb, barb etc.,

The egg scatters release eggs in a The egg scatters release eggs in a haphazard manner, scattering the eggs in haphazard manner, scattering the eggs in all directions.all directions.

Once the spawning is over, they often Once the spawning is over, they often consume the eggs.consume the eggs.

The eggs scatterers show no parental The eggs scatterers show no parental care.care.

Hence it is the job of the aquarist to Hence it is the job of the aquarist to protect the eggs from being eaten by the protect the eggs from being eaten by the parents.parents.

A thickly planted aquarium with less A thickly planted aquarium with less swimming space may e used for eggs swimming space may e used for eggs which are adhesive in nature. (eg. Eggs of which are adhesive in nature. (eg. Eggs of gold fish). gold fish).

This often helps the eggs from being This often helps the eggs from being eaten.eaten.

In the case of non-adhesive eggs (eg. In the case of non-adhesive eggs (eg. Eggs of danios), an aquarium with low Eggs of danios), an aquarium with low water column and a bottom laid with water column and a bottom laid with ebbles or marbles may be used.ebbles or marbles may be used.

The eggs scatters usually show less The eggs scatters usually show less interest in the eggs while the spawning is interest in the eggs while the spawning is in progress.in progress.

They start feeding on eggs only after They start feeding on eggs only after spawning is over.spawning is over.

Breeding traps and grids may be installed Breeding traps and grids may be installed for better survival rate of the eggs.for better survival rate of the eggs.

For eggs scatters, spawning grids are to For eggs scatters, spawning grids are to be placed with mesh size relative to the be placed with mesh size relative to the size of the eggs.size of the eggs.

Usually mesh size of 3x3 mm to 6x6 mm Usually mesh size of 3x3 mm to 6x6 mm are used.are used.

The grids can be constructed in two ways. The grids can be constructed in two ways. A net with required mesh size may be A net with required mesh size may be

attached to the upper side of a 5 cm thick attached to the upper side of a 5 cm thick plastic frame with frame size plastic frame with frame size corresponding to the inner dimensions of corresponding to the inner dimensions of the aquarium. the aquarium.

The frame should be lowered to the The frame should be lowered to the bottom of the tank so that a water column bottom of the tank so that a water column of 5 cm exists between the net and the of 5 cm exists between the net and the bottom of the tank.bottom of the tank.

Precaution must be taken not to leave Precaution must be taken not to leave space between the sides of the tank and space between the sides of the tank and the plastic frame, for the fish to enter.the plastic frame, for the fish to enter.

Another method is to place a piece of net Another method is to place a piece of net with required mesh size across the with required mesh size across the aquarium with the central portion aquarium with the central portion immersed below the surface providing immersed below the surface providing sufficient swimming space.sufficient swimming space.

Care must taken not to provide escape Care must taken not to provide escape routes while placing the net.routes while placing the net.

In both cases, the eggs fall through the net In both cases, the eggs fall through the net and are collected at the bottom of the tank.and are collected at the bottom of the tank.

Egg Depositors Egg Depositors Ex: Cichlids like Discus and Angle fish, Ex: Cichlids like Discus and Angle fish,

Firemouth cichlid, Oscar cichlid etc.,Firemouth cichlid, Oscar cichlid etc., The egg depositor are more for their The egg depositor are more for their

young than egg-hangers or scatters. young than egg-hangers or scatters. These are mostly cichlids when show These are mostly cichlids when show

parental care.parental care. They need substratum like leaves, rocks, They need substratum like leaves, rocks,

flower pots, tiles or slates to deposti the flower pots, tiles or slates to deposti the eggs.eggs.

Hence the spawning tank should contain Hence the spawning tank should contain hard substratum like rocks, slanting slate hard substratum like rocks, slanting slate or tiles etc., which can be easily removed.or tiles etc., which can be easily removed.

Most of the depositors select their own Most of the depositors select their own pair/ mate.pair/ mate.

It is be to remove the fry once they It is be to remove the fry once they become free swimming, even though the become free swimming, even though the fish show parental care.fish show parental care.

The tank should be similar water The tank should be similar water conditions and the water column very low conditions and the water column very low (5-10 cm).(5-10 cm).

If the fish fail to show parental care, If the fish fail to show parental care, remove the eggs along with substratum to remove the eggs along with substratum to another tank.another tank.

If the eggs are attached to the sides of the If the eggs are attached to the sides of the tank, remove they by scarping the side tank, remove they by scarping the side panes or by means a fine brush and panes or by means a fine brush and transferring the eggs to tank treated with transferring the eggs to tank treated with methylene blue.methylene blue.

The eggs are to be give profuse aeration. The eggs are to be give profuse aeration.

Mouth Brooders Mouth Brooders Ex: Ex: TilapiaTilapia Some of the egg depositor take the Some of the egg depositor take the

fertilized eggs into their mouth and fertilized eggs into their mouth and incubate them.incubate them.

These mouth brooders usually prepare These mouth brooders usually prepare breeding pits on the bottom sand on which breeding pits on the bottom sand on which spawning take place.spawning take place.

Hence the aquarium bottom should be Hence the aquarium bottom should be made of sand or fine gravel.made of sand or fine gravel.

In the case of tilapias, the female carries In the case of tilapias, the female carries eggs in her mouth. eggs in her mouth.

The eggs hatch inside the mouth and the The eggs hatch inside the mouth and the parent carry the fry also for some time.parent carry the fry also for some time.

Some of the mouth brooders tend to gulp Some of the mouth brooders tend to gulp the eggs.the eggs.

This may be due to numerous factor like This may be due to numerous factor like young and inexperienced spawners, young and inexperienced spawners, insufficient space or unfavorable insufficient space or unfavorable conditions.conditions.

This can be prevented by trapping the This can be prevented by trapping the female in a fine net without disturbing the female in a fine net without disturbing the fish much.fish much.

Then the fish is to be held in hand with the Then the fish is to be held in hand with the head immersed in a small bowl.head immersed in a small bowl.

Slowly open the mouth by applying Slowly open the mouth by applying pressure on to the lower jaw with index pressure on to the lower jaw with index finger.finger.

Then shake the fish gently in water, soon Then shake the fish gently in water, soon egg/ fry are released into the water.egg/ fry are released into the water.

Then these eggs/fry transferred to new Then these eggs/fry transferred to new rearing aquarium and given profuse rearing aquarium and given profuse aeration.aeration.