Betta fry are among the hardest fry to raise. Many people are fooled by how easily the male and female spawn and then think that all you have to do with the fry is feed them BBS (baby brine shrimp) and that’s all. In truth, keeping Betta fry alive long enough to get them past the first two weeks of life is very hard. There are many ways to keep the fry alive. However, I am going to tell you about what I do to keep them alive.
The male Betta makes his nest under half of a styrofoam cup that is taped at the six-inch water line. There are plastic or live plants in the tank and a sponge filter that has not yet been turned on. After the pair has spawned you will need to take the female Betta out of the tank, or the male might kill her. The male will stay in the fry tank, which should be between five and ten gallons in size. The top of the fry tank should be tightly covered. I use Saran wrap and plastic taped to the top of the tank, but not taped at the front. I like to use java moss in the fry tank because it allows them to hide. Depending upon the temperature of the water (it is best at 78-86 degrees F) the eggs will hatch between 24 and 48 hours after being laid. When the fry first hatch they will hang their tails down out of the bubble nest and tend to fall out of the nest all the time. The male will put any of the eggs or fry that fall out of the nest back into it. The male can not eat during this time.
By the 2nd or 3rd day, the fry will begin to free swim and the male will need to be taken out of the tank. The fry seem to get smaller at this stage because their yolk sacks are being absorbed. Now you can begin to feed infusoria. You can culture infusoria by taking old tank water and putting it into a jar with soft lettuce. If you begin the infusoria before the pair spawn it should be ready by the time the fry are fry swimming. To harvest the infusoria, take a light and shine it to one spot of the jar for about 3 minutes, then take an eye dropper and suck up the water were the light was. Some breeders like to put liquid fry into the tank for the infusoria to eat. When the fry are about 4 days old they can begin to feed on microworms and newly hatched brine shrimp. It is best to feed them 2 or more times a day. Usually some of the fry won’t make it past this stage, but the hardier ones will continue to eat and grow.
When the fry are about one month old, they will stop dying off and will begin to show colors like red, blue and black. Other colors like yellow and marble do not show till the fry are older. The fry should be around ¼-inch long or larger. There will also be smaller fry but they may just be late bloomers and they often turn out to be the best. However; the larger fry may begin to kill them off. The fry also begin to “play” fight, but this is not a problem and they should be left together. At two months, you know how many fry you will get from the spawn. Most of the time, if there were 50 eggs you will get 25 fry, and if there were 100 eggs then you end up with about 50 fry, so about half of the original number of eggs will become full-grown Bettas. The fry should be eating and growing fast now, but it is still hard to tell males from females. Sometimes the males anal fin will be longer and come to a sharp point. Now is the best time to take newly dropped guppy fry and put them in with the Betta fry. This way the guppy fry can teach the Bettas how to eat dried foods like blood worms and tubifex worms.
By the time the fry are 3 months old you can begin to tell who is going to be male or female. The males will be larger and have longer fins while the females have shorter fins and, in light colored females, you can begin to see eggs form in the middle of their bodies. Jarring will also begin now. It is best to use 2-liter to 1-gallon size jars for the males and to just let the females stay in the tank together. They should also be fed freeze-dried blood worms in the morning and live foods in the evening.
As the fry turn 4 months
old, a large amount of fin growth begins. The females are now larger and full
of eggs, and the males are making large bubble nests and flaring. It is best
to do water changes in 2-liter jars every 2-3 days and every 3-4 days in the
1-gallon jars. It is a good idea to put cards between the males’ jars
and for 2 hours every day, remove the cards and let them flare/display to each
other. Also, if you have not done this by now, it is time to cull the runts,
the deformed or any Betta that just does not look right. You need to check for
missing pelvic fins and curves in the spine, and also look for bends in the
fin rays. Now that the fry are old enough to spawn, you will need to go through
it all over again. But now you know what to do and hopefully you will get better
and better at raising fry.
Last updated 30 June 2003, 1940, BL