BREEDING
Under natural conditions fishes have certain seasons to mate and produce
young, but in an aquarium where the conditions are almost constant, it is very difficult
for the fish to adjust their biological clock for this activity. But you can induce breeding
in them by changes in water conditions or temperature depending on the species and its
requirements and make them breed. That is how most of the aquarium fish have been bred
and sold. Some of the tropical fishes like Live bearers can breed any time of the year and
do not need much inducing. Most of the tropical fish continuously produce eggs and sperms in
their bodies and they continuously breed. The bubble nesters, cichlids, barbs and Live bearers
all show continuous if irregular cycles of breeding and it is only necessary to provide
proper conditions like separate tank to collect eggs and rear them. Eggs are often laid
even in community tanks without the fish keeper even knowing it.
The success of the experienced breeder then is usually the result of
careful observation of his fishes and his skill in providing the favourable conditions
for them. Some fishes rarely breed in captivity and it is unknown if any body had succeeded.
Selection of breeding pair and Sexing
It is often cheaper to buy young fishes and bring them up to maturity by
regular care and feeding. At least six healthy specimens of uniform size must be obtained
and given an aquarium to themselves. The average age by which maturity occurs in tropical
fish is 8 months. In live bearers it is much earlier. Maturity is evidenced by the size
and colour and sex characteristics.
Sexing the fish is the next difficulty. Fish sex organs are internal and
so only secondary sexual characteristics such as colouration, size , behaviour and the
existence of features such as gill tubercules of the male gold fish , oviparous tubes
of certain charachins, can be used at first sight. Live bearers are very easy to sex as
the males have their anal fins differentiated into a rod like gonopodium (2) and frequently
show colours which are far more brighter than the females. Many fishes, particularly in
the charachin family do not show any features however that help distinguish females and
males. But characteristics such as deeper and plumber bodies of females and the chasing
by the males may be the guide for the breeder. The best method of all in breeding , in
fact most useful with charachins is to allow the parents to select themselves within a group
of say, six of the fishes. Careful watching of the group for a time will reveal that
certain pairs are showing obvious preference for one another society. Such a pair often
swim together and are seldom apart. They are most likely to mate when placed in a breeding
tank.
Conditioning the breeding Quarters
The breeding pairs selected from a stock are usually conditioned in separate
aquaria, males in one and females in another, or each on either side of a central dividing
glass partition in a 24 inch tank. Conditioning for breeding involves giving them all the
nutritious food such as worms, mosquito larvae etc.. Feeding is continued in this manner
for a week or so and when the female is plump with ova and the males are displaying their
intense breeding colours then fishes are let together by removing the glass partition.
The breeding tank should also be prepared depending on the fish we are going to breed.
1 feet tank should suffice in most cases. The water should be 6 inches deep and should be
soft or neutral depending on the species. The tank should have breeding trap at the bottom
or well planted at the bottom with aquarium grass. The fish are let together usually on the
early morning and at first light they would usually start breeding. The spawning will last
a few hours with intervals of rest, some eggs will be eaten by the parents, but most will
get collected at the trap or plants. When spawning is over remove the parents. If spawning
does not take place try replacing the part of the water with cooler fresh water. If still
no eggs are laid then remove the fish to respective partition sides and try after another
week. Fishes that have spawned should be fed well and given rest as this is an exhausting
process especially for females. The above is applicable to barbs and charachins mostly.
Zebra fish and danios are avid egg eaters and a layer of pebbles or a net can be placed at
the bottom which will allow the eggs to pass through collect the bottom.
Long conditioning periods are not necessary for live bearers, cichlids or
bubble nesters. All that is needed for live bearers is to place the female and males
together and they would readily mate. When the females are plump with young place the
female in a well planted tank and remove the parent once the young are born. Try not to
move females nearing delivery time. A small plastic tub is enough with some floating and
immersed plants.
Plants are not much use in cichlid tanks, except angel fish which use
broad leaves for their egg, but rock work needs to be present. A 1.5 ft tank is necessary
and female can be removed if the male becomes aggressive. But leave the male to look after
the fry.
Bubble nesters may be bred in a tank similar to the one described for
general account. After the eggs are laid in the bubble nest remove the female fish.
Males can be left to look after the young for a week. Siamese fighter and dwarf gourami
fry need infusoria. But young fish of other species can be given egg yolk suspension. Keep
the water surface warm and from dust and oil as the fry develop the labyrinth organ during
the second and third week.
Feeding the Fry
Infusoria: Can be obtained in two ways: (a) It can be collected from ponds
by sweeping the water with a silk or nylon net, rinsing the inside of the net in a jar of
water (b) It can be cultured in a jam jar. Put a pinch of pond mud or earth from a damp
corner of the garden into a jar, fill it with water from an aquarium and then add a teaspoon
of milk or crushed lettuce leaf, an old banana skin or a slice of soft potato. Keep the
mixture in a fairly warm place. After a day start the second jar adding also a little of
water from the first jar.
  In two or three days the first jar is ready, strain off the Infusorians
through silk, do not add the culture solution direct into the tanks. Keep a succession of
jars going, for each jar soon becomes too foul for further use. Bacteria growing in the
water causes the smell but they are the organisms on which the Infusoria from the pond mud
feed. A drop of water from a good culture placed on a glass over a black paper should
reveal moving specks in it to magnifying glass examination, and the culture is not ready
unless it shows this.
Egg Yolk : Yolk from hard boiled eggs are excellent for small fry. You can get a suspension
of this into your fry tank by squeezing the yolk through a fine mesh cloth. Beware this food
can rot very fast and must be fed in small quantities only. You can prepare a suspension
in a small bowl and keep it refrigerated and add a few drops to the tank every hour.
Micro Worms : Micro worms are very useful for fry just past the Infusoria stage. Dealers
supply them and a culture can be started by adding a few to a shallow layer of a paste of
boiled oatmeal containing a little yeast, placed in a small glass pot. Wetted match sticks
stuck in the medium become covered with tiny worms, which can be rinsed into the fry tank.
Keep the jar at 70F and renew any that become too "high" by adding a little of the old
medium to a jar containing fresh food.
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