7-07-2021, 21:36
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If you take good care of your aquarium pets and feed them well, one day you may notice tiny fry swimming around in the aquarium. Although the occasional fry are always interesting, there are several ways to improve their survival rate or increase their numbers if you plan to sell them for profit.

1. Protect the eggs from the producers

Many fish show no parental concern for their offspring and will happily eat their own eggs that they have just laid. So the first thing to do is to save the eggs from the producers' temptation to eat them. To do this, use one of the following methods:

  • If the eggs are sticky, you can provide spawning places in the aquarium, e.g. dense plants (ferns, mosses), ceramic tiles or spawning cones. Once the eggs have been deposited, you can move the object or plant bush with the eggs to a safer location.
  • If sticky eggs are deposited on the aquarium glass or other stationary objects, you can remove the producers from the aquarium. Another way is to collect the eggs by hand, rolling them up with your fingers or using a plastic credit card.
  • If the eggs are not sticky and are scattered chaotically, you can use coarse gravel as a substrate so that the eggs can fall into crevices between rocks where the parents cannot reach. Another similar technique is to place a separator net just above the bottom of the aquarium so that the eggs can fall between the cells. Some aquarists place moss or other dense plants under the net as additional protection.
  • Most cave fish such as dwarf cichlids assiduously protect their clutches, but juveniles often tend to eat them. If you want to keep the eggs safe, use a suitably sized grotto, coconut shell or PVC tube in which the fish could spawn and then move them to another tank as soon as the eggs are expelled.
  • Some species of African cichlids incubate the eggs in their mouths. However, some aquarists prefer to deprive the female eggs (or fry) to prevent accidental ingestion of the calves.

Once the eggs have been isolated, it is time to incubate them. The eggs, especially unfertilised eggs, are susceptible to fungal diseases that can spread quickly and ruin the entire clutch. Larger eggs, such as African cichlids, can be placed in a tank with increased aeration of the water. You can add a few drops of methylene blue (until the water turns slightly blue) or a few alder cones as a mild fungicide, and then do a couple of 50% water changes in the aquarium after the larvae have hatched. Remove the eggs on which the fungus has formed in good time.

Fish eggs.

2 Separate the parents from the fry.

The fry have not yet emerged from the danger zone after hatching. Separating fry from the adults not only prevents them from eating, but also allows them to grow larger and faster since there is less competition for food. In addition, it is best to keep the newborn fish in a smaller aquarium so they do not have to expend much energy swimming to get to the food. For viviparous fish, you can place the pregnant female in a spawning tank and then set her aside after she has hatched all the fry.

When the fry become larger and stronger, move them to a larger rearing tank so they have more room to swim. If some fry grow faster than others, you may need to separate them by size into several tanks to prevent cannibalism and reduce competition for food. This sorting process also gives you the opportunity to cull diseased fry, if necessary, to prevent the spread of defective genes.

3. provide plenty of shelter

For those who do not have the space for an additional fry rearing tank, you can instead try colonial rearing, in which parents and fry are reared in the same tank. While this approach may not produce the highest number of offspring, it is certainly easier in terms of time, cost and space. To increase the survival rate of the fry, you need to create plenty of nooks and crannies for them to hide in.

If you prefer natural hiding places, dense thickets of living aquarium plants also serve this purpose. Some species of fry prefer to hide in a pile of rocks with small spaces between them, where they could squeeze through. Finally, various aquarium decorations and small artificial caves can provide additional hiding places for the fry that they can use in case of danger.

4. Watch the water quality

Fry are less hardy than adult fish and may therefore be more sensitive to any toxins or excess waste in the water. Be sure to include gentle filtration, such as a sponge filter, and flush the filter regularly to prevent fecal clogging.

Homemade miniature aquarium siphon.

Because the fry feed frequently, the water in the aquarium will have to be changed daily or several times a week. To ensure that the fry are not accidentally sucked in when cleaning the aquarium, you can use a tiny siphon in the form of a long air tube. Attach one end of the tube to a stick with elastic bands and place this end in the aquarium water. The wand will allow you to move the siphon around easily and avoid getting the fry in the tube. Use your mouth to create a vacuum so that the water starts to flow through the tiny siphon and then place this end in a white bucket to collect the dirty water. The white bucket makes it easier to see the accidentally sucked in fry.

5. Feed the fry tiny food several times a day

Fry have tiny mouths and tiny stomachs and, just like human babies, they need to eat constantly throughout the day. The newly hatched fish have a yolk sac, which they feed on until they are strong enough to swim freely and search for food. Then they need several small meals, up to 3-5 times a day if possible. You can set an alarm on your phone or use an automatic feeder. The smallest newborn fry (e.g. rainbow fish and tetras) should be fed with microscopic foods such as live dust and infusoria. Larger fry (e.g. livebearers and African cichlids) can be fed with milled Artemia flakes and nauplii, which are the n°1 food for the fry. They do not only contain very nutritious proteins and healthy fats, but they also swim around in the water column and arouse the hunting instincts of the young fish.

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