Breeding Goldfish is not an easy task. It is a fun-filled, worthwhile experience. But, it is also time consuming. If you want to breed Goldfish,you need to know the following:
- Age of maturity
- Determining the gender of the Goldfish
- Reproduction Strategies
- Breeding Tips
- Encouraging your Goldfish to spawn
- Identifying Eggs
- Egg Care
- Hatching and Raising Fry
- Fry Care
- Filtration, Aeration, and Heating
- Water, Lids, and Water Depth
- Lighting and Cleaning
- Goldfish Growth Rates and Color Changes
Age of Maturity
All Goldfish varieties, both male and female attain their maturity
when they grow 3 to 5 inches (7.5 to 11 cm). Their maturity age
differs from different types of fish and their living conditions.
Nevertheless, they reach the maturity size from 10 months to 36 months
Determining the gender of the Goldfish.
It is impossible to differentiate between the sexes of Goldfish until
they reach maturity. Only professional breeders can tell the
difference. The internal and external difference between a female
and a male are as follows. We can only see these differences after
they attain maturity.
1 & 2 are the female anal openings. They are larger,
protrude slightly and is round in shape. The anal fin
is thicker and has a heavier first anal fin spine. Themale is 3 & 4. The male's opening is small and oval
with no noticeable anal fin thickness.
|Internal body location
|In Gill plates
||It has white prickles
called tubercles present
on gill plates and head.
|It has white prickles
present on gill plates.
|Vent ( where wastage
comes out )
|Smaller opening and
goes in (concave)
|Larger opening and
sticks out (convex)
||Smaller, more firm and
may have ridge
|Larger, fat, no ridge
and more supple.
|External body location
||Chased and attacked
||It appears slender,
longer and symmetrical
from the top
|It appears fatter, shorter
and asymmetrical from the
top when it carries eggs.
When a male and a female Goldfish attains at least 3 years of age,
move the couple into a separate 20-gallon tank with plants. To
encourage breeding, you should raise the temperature of the tank
to 70 - 74 degrees F during the breeding season (spring). Sexing
occurs in the wild during breeding
season only. Through spawning
method, we can breed in spring
Female goldfish are plumper than
the male of the same species. The
males have white little bumps on
their heads. These are called tubercles and they become more
visible during spawning.
The vents of females enlarge and turn outwards, while the male
vent remains the same. Behavioral changes during the mating
season includes the males chasing the females around the tank.
You can use this as an indicator to separate the pairs. These
differences become much more apparent as spawning time approaches. The male's opening is small and oval with no
noticeable anal fin thickness.
These differences become more apparent as spawning time
approaches. The female opening will be larger and more distended
when the eggs are ripe. When the male is ready, milt may be
pushed out of the ventral opening by running a finger lightly
along the sides of the fish. But, this shouldn't be necessary as the
tubercles can be plainly viewed.
Six types of reproduction can occur in fishes.
2. Egg depositors
3. Egg scatters
4. Live bearers
5. Labyrinth fish
6. Mouth brooders
Here naturally all varieties of Goldfish are reproduced their fry through Egg scatters strategy.
If the fish reproduces through brood strategy, one of the parents
takes care of the eggs and fry. They protect their eggs or fry from
The egg depositors lay their eggs under any object like gravel or
plant leaf or rocks or in nest or on a surface.
The 'egg scatters'type of fish swims into watery plants or sides of
objects or in gravels and scatters its eggs on them. In this type,
both male and female scatter their eggs and sperm respectively by
pushing against each other. Sometimes, parents may eat their own
eggs. In this type, we should protect the eggs from the parents and
In Live bearer's, female fish develop the eggs inside the body after
mating. After a certain period of time, live fry are born on theirown.
Labyrinth fish protect their eggs in bubble nests. The male makes
bubble nest using saliva and water. The male protects the egg until
fry are born.
Some species of fish protect their fertilized eggs in their mouth
until they hatch.
By this time, both male and female does not eat much.
1. Changes in water temperature, direction of change is dependant
on the species.
2. Changes in water depth and direction of change is also
dependant on the species.
3. Changes in feeding - usually increase in live foods.
4. Changes in tank mates - usually separate and re-join male(s) and
female(s) or introduce new fish together.
5. Changes in water quality - usually cleaner water with a greater
pH closely matching that found in the wild.
6. Changes in lighting - usually increase in day time
Encouraging your Goldfish to spawn
Spawning of fish is an artificial method formating fishes. This
method is worked well for fish which, belongs to Egg depositors
and Egg scatters reproduction type.
Goldfish are egg scatters so they prefer to breed on soft location.
Hair-like structures of algae plants and soft aquarium plants help
the fish to spawn.
We can induce spawning in Goldfish by the following ways.
1) Replace 20% of the water in their tank with fresh tap water.
This will induce the pair to spawn. But make sure you don't
change more than 20% of the water, as this may stress your fish
2) A gradual change in diet may also induce spawning. Normally,
they respond to live food like brine shrimp, tubifex or black
worms, daphnia, etc. But, remember not to change their dietovernight.
Live food gives the extra nutrition required to produce
vast quantity of eggs and sperm. Feeding fish to induce spawning
is called conditioning.
3) Gold fish can be spawned easily for temperature changes
during spring season.
4) If the above three methods doesn't help, then separate the male
and female on the first day of spring and put them back together
after 15 to 18 days in the spring season, then they will spawn.
Just keep in mind that goldfish do not do well with drastic
changes. Any change in diet or habitat has to be gradual.
Now, the fish is ready to mate. After spawning, increase the
temperature of the tank from 70 to 74 degrees F. Before mating,
female fish carries unfertilized eggs. At the time of mating, male
releases sperm and female releases unfertilized eggs. Sperm and
unfertilized eggs get together to form fertilized eggs on the leaves.
Female may lay eggs from 10 to 1000 eggs.
After spawning, increase the temperature of the tank from 70 to74 degrees F. Before mating, female fish carries unfertilized eggs
At the time of mating, male releases sperm and female releasesunfertilized eggs. Sperm and unfertilized eggs get together to form
fertilized eggs on the leaves. Female may lay eggs from 10 to 1000
Ideally, you should remove the eggs from the main tank and
transfer them into a dish no more than six
inches deep so that you can wash the eggs.
Otherwise, we can separate parents to
another aquarium to prevent them from
eating the eggs. If eggs are scattered, we can
remove those from the mating tank by using a siphon. Just make
sure that the temperature of this water is the same as the
temperature of the water in the tank.
After cleaning the eggs, place them in a 20-gallon tank. Maintain a
steady temperature of 70 degrees Fahrenheit.
Some eggs will be white in color while others tanned. The clear,
white ones are the fertile eggs. You should remove the infertileeggs as they are susceptible to fungal infections that could kill the
fertile eggs as well. We can remove infertile eggs using finger nail
tweezers. The fertile eggs will hatch in four to five days time. To
prevent egg fungus, add dilute solution of methylene blue to the
water tank which has the transferred eggs. We can keep all the
eggs first in methylene blue solution for one day. Then
remove the unfertile eggs and transfer the fertile eggs
to a fresh water tank. Frying does not do well in
methyelene blue solution.Now, let's see stage by stage
how an egg becomes a fry or hatchling. The egg shown
in the picture is three days old. It is a well developed embryo.
This is the embryo at the beginning of the fourth day.
Now, let's see stage by stage
Goldfish requires more oxygen in the development stage. Use of
mud and organic debris is not suitable to the development ofeggs.
At birth, Goldfish fish are tiny… only onesixth of an inch! They
are translucent and have large black eyes.
This is a nine-day old fry.
After the hatchling comes out, we
have to care until it attains full
First, move the hatchings into larger
tanks of 20 gallon or divide them to
Your fry likes warmer temperatures, so maintain
the temperature at 75 degrees F.
Unwanted organisms can be grown in the tank. In order to
prevent from growing such organisms, add 2 spoons of salt per 10
to 12 gallon water. Don't add too much of salt since Goldfish does
not like salty water.
Please cover the water tanks with glass to keep
moisture in. You should provide more oxygen supply to the fry.
Filtration and Aeration:
To provide bacteria in the tank, use filter with carbon and floss.
Fix filter in the corner of the tank. Otherwise, you can also makeuse of sponge filter. Light aeration is needed for the egg until it
starts to feed. We can provide light aeration in the filter by flow
of air bubbles. Don't feed fry until it can swim.
Lighting and cleaning
If you start feeding them, you have to clean the tank on a regular
basis. Before feeding, make sure the tank is clean. Provide light
above the tank after you add food in the tank. This will be very
helpful for the fry to find their food.
Feeding for Fry
Taking their tiny size into consideration, it is very difficult to feed
young Goldfish. You should drop sufficient food for them to eat.
But, remember to clean the tank before adding fresh food every
few hours to prevent stagnation. For the young fish to survive,
they need to be fed often and sensibly to keep them alive and
growing. You can feed live foods, various sizes of micro worms,
daphnia, cyclops, and euglena. Make sure live foods are free from
parasital or bacterial infection. You can feed fry foods, pearls and
baby brine shrimp
Brineshrimps (Artemia salina)
Most fry are large enough to eat brine shrimp as their first food,
especially if you give them newly hatched brine shrimp. Very
small fry should instead be fed infusoria initially, and brine shrimp
can be introduced as a second food. If you feed your brine shrimp suitable food, they will grow large enough to be used as food for
adult fish as well. Growing large brine shrimps is an inexpensive
way of providing your fish with much appreciated livefood and is
especially recommended when you wish to induce spawning.
Just like infusoria, brine shrimp is easy to cultivate at home. You
can buy a brine shrimp hatchery from your fish store or fix one
yourself. Brine shrimp will hatch even in bottles! Some brine
shrimp hatcheries will require an air stone connected to an air
operated pump. Other brine shrimp hatcheries can be attached
inside or outside the aquarium.
If you want to fix your own brine shrimp hatchery in a bottle,you can use a clean milk bottle or a similar container. Boil some
water, three quarters of a pint is enough, and let it cool down
before you fill the bottle. Add one teaspoon of aquarium salt tothe water and put the bottle in a warm room. It is possible to use
ordinary cooking salt instead of aquarium salt, but the result will
usually not be as good as aquarium salt. Insert an air stone in
the bottle to provide oxygen. Place a pinch of brine shrimp eggs in
the water and wait for them to hatch. The water temperature must
never go below 15 degrees Celsius, but this is usually not a
problem in a temperate room. Brine shrimp eggs will typically
hatch after 48 hours or even earlier.
By setting up new bottles, you can make sure that you always
have suitable size brine shrimp for your fry Brine shrimp eggs can
be bought in most pet shops and fish stores. If you use eggs with
shells, you must turn off the air stone in the hatchery to make the
shells sink to the bottom. The hatched brine shrimp will stay a few
inches above the bottom and can be easily removed. It is
important to separate the brine shrimp from the shells, since shells
might get stuck inside the fry if they consume the eggs. You can
also buy shell-free brine shrimp eggs.
Water Fleas (Daphnia)
Water fleas can be hard to disinfect properly, so if you want tofeed your fry daphnia, you must obtain it from a source that you
can trust and that you know have no sanitary problems. The same
is true if you plan to raise your own daphnia for the fry. You
must make sure that you begin with a disease-free starter culture.
Once you have obtained a proper starter culture of daphnia, the
rest is easy. Fill a plastic container with 5 gallons of tap water and
let the water stand for roughly 48 hours at room temperature.
Obtain a handful of manure from a stable. You may also require a
nylon bag. You can produce one yourself from a pair of nylon
stay-ups or use the type of nylon bag that comes with washing
machine tablets. Place the manure in the nylon bag and submerge
the nylon bag in water. After roughly 7-10 days, the water would have turned cloudy, which means the water is now filled withmicro organisms for the daphnia to feed on.Add the daphnia to
water and wait. The culture will take care of itself for the few
weeks during which the daphnia grows large and abundantenough
to be used as fish food. The easiest way of removing daphnia is to
use a fine meshed net.
White worms are the much appreciated fry food that can be
cultured at home. You need some moist and nutritious garden soil
for the white worms to grow. Fill 75% of a shallow box with
garden soil. If necessary, water the soil until it is quite damp.
It is important that the soil is never allowed to dry out, but
waterlogged soil is just as bad. Add the white worm culture to the
soil together with a few small pieces of moist white bread. Cover
the box with a lid. The box or the lid must have some air holes toallow for ventilation. Put the box in a dark place where the
temperature is around 16 - 18 degree Celsius. Add new bread to
the box every 3 - 4 days and make sure that the soil is constantly
moist. If you find any uneaten food, you should remove it before
it turns bad.
When it is time for you to collect white worms for your fish, you
just spoon out some soil from underneath the bread. You will
naturally find one of the largest congregations of white worm
right beneath the food pieces. Pour the soil with the white worms
into a bowl or dish filled with water. When the worms separatesfrom the soil, you can easily collect and drop them into the
||No. of times per day
|After 48 hours
||You can start the first feeding
|For first 4 weeks
||Feed 3 times
|Up to 4 months
|After 4 months
Please provide large tank according to their growth rate. After 2
to 3 months, fry can grow large enough to live with parents. At
that time, we can put fish with their parents and other fish.
Growth rate and color changes in young ones
Goldfish can grow up to 1 to 4 inches (2.5 to 10) years. Common
Gold fish and Comet grow up to 5 inches (12.5 cm) in two years.
Single tail varieties reach 4 to 6 inches in length (10 to 15.5 cm)within 32 months.
Fancy Goldfish can grow up to 3 to 5 inches (7.5 to 12.5 cm)
within 30 months.
They may take one or two years to
change the brown color to golden color
or their parents color. Some Common
and comet Goldfish change their brown
color when they attain a growth of an
inch in length. Other varieties can
change their color to orange or gold when it attain a growth of 4
to 5 inches. Most Common Gold remain in their natural color.
Fancy and Shubunkins Goldfish develop their colors when they
attain a growth of an inch in length. They develop the best color
and are ready to breed earlier than Common Gold.