Breeding Pygo. Nattereri Piranhas
If you want to breed red bellied piranhas you need to have a larger aquarium, by that I mean
100 gallons or more, and it has to have a strong filtration system.
Choose your Piranhas
In order to breed piranhas you need to choose the right fish. You need a shoal of at least 4 to
6 fish with an average size of at least 6 to 7 inches. This will ensure the fish are either close
to, or at, sexual maturity.
Red bellied Piranhas are not sexually dimorphic; that means you cannot tell females and
males apart by just looking at them with the naked eye.
However, If you have had previous experience in breeding piranhas, you may possibly be
able to tell the male and female apart once they are in the spawning period.
The best thing to do is to start your aquarium with juvenile fish of maybe an inch and a half to
two inches long. It is difficult to go wrong by purchasing your piranhas in this size range and
then growing them up too adulthood. It's best to buy at least 10 as you will probably lose
some to injury and territorial aggression along the way.
Signs of Breeding
If you notice some changes in your piranhas behavior, possibly more aggression than
normal, or pairing off and separating themselves from the rest of the shoal, then the spawning
process may be underway.
A very good indication is noticing the pair (female/male) darkening in color (see illustration
below). They will turn black and have a purplish tint with highlighted sparkle when under
lighting. This display is more likely to start after tank maintenance and water changes.
Nest Building
Shortly after pairing off from the rest of the shoal the couple will look for and pick out a
location to build their nest.
You will find the male is the more aggressive of the two to get underway, but well may be
accompanied by the female.
The male will tilt his face down into the gravel and shift it around, biting and blowing it to make
it fit for ideal breeding conditions.
If the same location is used over a period of time, the gravel will start to become finer from the
male/female biting on it and crushing the rock.
Small pieces of saved food will be placed into the gravel by the pair when building the nest.
This is for the freshly hatched fry to get a head start on feeding, as they will not be strong
enough to surface for a few days after hatching.
Breeding in the nest
When the male is finished with the nest building, the female is usually within a few inches of
the male. However, at times she will be further away, sometimes even on the other side of the
tank.
You will also notice that the female is usually sitting higher in the water column than the rest
of the piranhas.
She is now full of eggs and perhaps the air in all the eggs sacks make the female float higher
than normal.
The male will brush up against her in order to direct her towards the nest. She won't put up
too much of a fight at this time and will slowly pass by the nest a few times.
Once they settle in the nest they will go over the nest and fine tune it a little bit to make sure
they have it all set, and ready for the breeding stage to begin.
When the female is ready to release her eggs, they will be side by side, with their noses down
into the gravel and tails straight up.
They will wiggle together, as the female releases the eggs and the male starts to fertilize the
eggs as they are released.
They will continue this process over and over, while nipping at each other and switching
positions from side to side.
Any intrusions from other tank mates at this time is crossing the line, and they will be very
quickly chased away with a great deal of force by both the male and the female.
The overall process of the breeding will take several hours and runs until very late in the
evening. The female will release 1000 to1500 eggs and the male will need to fertilize them all
in order for them to be fertile.
When the pair have spawned the male usually guards the eggs for two reasons: completing
the fertilization process, and protecting the eggs from predators.
A nest with fertile eggs
After the pair have finished breeding in the nest, the male is usually the one that will guard the
nest. The female will often stay within a foot of the nest, but the male is usually the one who is
present at all times.
The eggs should be clustered around the nest and there should be a thousand or more,
depending on the size of the female that released them. The eggs if fertilized properly should
be an orange sort of color and be covered in a thick layer of milt.
Hatching fry and growth rate
The fry will start to hatch within 48 hours.
The best way to have them hatch is to remove them to a holding tank.
Be sure to remove the white infertile eggs so they do not spread a fungus over to the
fertilized eggs.
Once the fry begin hatching they will pop their tails out through the eggs sacks, creating a
spinning motion.
Many people wait until their tails start to spin before removing them to the holding tank. Either
way, use water from the parent's tank in the holding tank to avoid unnecessary stress.
You must be very careful when removing the eggs/fry as piranhas become very aggressive
and protective of their fry & eggs.
Keep the fry in a bare tank, with only a sponge filter. The fry quickly absorb their yolk sac and
you will need to have food ready for them! You will have to feed them newly hatched brine
shrimp. Ask your fish store about the brine shrimp eggs and how to properly hatch them.
The fry will grow very fast, but they must have good water parameters, water changes and
freshly hatched brine shrimp.
If you want to breed red bellied piranhas you need to have a larger aquarium, by that I mean
100 gallons or more, and it has to have a strong filtration system.
Choose your Piranhas
In order to breed piranhas you need to choose the right fish. You need a shoal of at least 4 to
6 fish with an average size of at least 6 to 7 inches. This will ensure the fish are either close
to, or at, sexual maturity.
Red bellied Piranhas are not sexually dimorphic; that means you cannot tell females and
males apart by just looking at them with the naked eye.
However, If you have had previous experience in breeding piranhas, you may possibly be
able to tell the male and female apart once they are in the spawning period.
The best thing to do is to start your aquarium with juvenile fish of maybe an inch and a half to
two inches long. It is difficult to go wrong by purchasing your piranhas in this size range and
then growing them up too adulthood. It's best to buy at least 10 as you will probably lose
some to injury and territorial aggression along the way.
Signs of Breeding
If you notice some changes in your piranhas behavior, possibly more aggression than
normal, or pairing off and separating themselves from the rest of the shoal, then the spawning
process may be underway.
A very good indication is noticing the pair (female/male) darkening in color (see illustration
below). They will turn black and have a purplish tint with highlighted sparkle when under
lighting. This display is more likely to start after tank maintenance and water changes.
Nest Building
Shortly after pairing off from the rest of the shoal the couple will look for and pick out a
location to build their nest.
You will find the male is the more aggressive of the two to get underway, but well may be
accompanied by the female.
The male will tilt his face down into the gravel and shift it around, biting and blowing it to make
it fit for ideal breeding conditions.
If the same location is used over a period of time, the gravel will start to become finer from the
male/female biting on it and crushing the rock.
Small pieces of saved food will be placed into the gravel by the pair when building the nest.
This is for the freshly hatched fry to get a head start on feeding, as they will not be strong
enough to surface for a few days after hatching.
Breeding in the nest
When the male is finished with the nest building, the female is usually within a few inches of
the male. However, at times she will be further away, sometimes even on the other side of the
tank.
You will also notice that the female is usually sitting higher in the water column than the rest
of the piranhas.
She is now full of eggs and perhaps the air in all the eggs sacks make the female float higher
than normal.
The male will brush up against her in order to direct her towards the nest. She won't put up
too much of a fight at this time and will slowly pass by the nest a few times.
Once they settle in the nest they will go over the nest and fine tune it a little bit to make sure
they have it all set, and ready for the breeding stage to begin.
When the female is ready to release her eggs, they will be side by side, with their noses down
into the gravel and tails straight up.
They will wiggle together, as the female releases the eggs and the male starts to fertilize the
eggs as they are released.
They will continue this process over and over, while nipping at each other and switching
positions from side to side.
Any intrusions from other tank mates at this time is crossing the line, and they will be very
quickly chased away with a great deal of force by both the male and the female.
The overall process of the breeding will take several hours and runs until very late in the
evening. The female will release 1000 to1500 eggs and the male will need to fertilize them all
in order for them to be fertile.
When the pair have spawned the male usually guards the eggs for two reasons: completing
the fertilization process, and protecting the eggs from predators.
A nest with fertile eggs
After the pair have finished breeding in the nest, the male is usually the one that will guard the
nest. The female will often stay within a foot of the nest, but the male is usually the one who is
present at all times.
The eggs should be clustered around the nest and there should be a thousand or more,
depending on the size of the female that released them. The eggs if fertilized properly should
be an orange sort of color and be covered in a thick layer of milt.
Hatching fry and growth rate
The fry will start to hatch within 48 hours.
The best way to have them hatch is to remove them to a holding tank.
Be sure to remove the white infertile eggs so they do not spread a fungus over to the
fertilized eggs.
Once the fry begin hatching they will pop their tails out through the eggs sacks, creating a
spinning motion.
Many people wait until their tails start to spin before removing them to the holding tank. Either
way, use water from the parent's tank in the holding tank to avoid unnecessary stress.
You must be very careful when removing the eggs/fry as piranhas become very aggressive
and protective of their fry & eggs.
Keep the fry in a bare tank, with only a sponge filter. The fry quickly absorb their yolk sac and
you will need to have food ready for them! You will have to feed them newly hatched brine
shrimp. Ask your fish store about the brine shrimp eggs and how to properly hatch them.
The fry will grow very fast, but they must have good water parameters, water changes and
freshly hatched brine shrimp.
holy moly 
