Make sure you only breed fish of the same species. While it may be possible for two different species to reproduce, there’s a good chance that the resulting hybrid will be feeble, deformed, or sterile. Pass over fish that appear sick, injured, or deformed. They’re less likely to produce healthy offspring. [1] X Research source If you’re at a loss for how to differentiate the sex of your fish, take them to an aquatic veterinarian or breeding specialist to have them examined by an expert.
For most species of fish, you’ll need a spawning tank with a capacity of at least 5–10 gallons (19–38 l). When you first transplant the parent fish to a new tank, it’s best to keep the conditions as close to their old tank as possible and make necessary adjustments very gradually to help them get acclimated.
Most average-sized aquarium species like Bettas and Angelfish prefer a live diet of fresh or frozen brine shrimp, white worms, or daphnia. [4] X Research source It’s best to condition fish for roughly 2 weeks before they begin mating. Learn about your parent species’ natural diet to know what sorts of foods you should be feeding them in the early phases of breeding. Most fish do best with a balance of fresh herbaceous plants, as well as live offering like brine shrimp. [5] X Research source
Read up on your species in a fish encyclopedia. You may also be able to find books and manuals that delve deeper into the specifics of aquarium breeding.
In order for Discus and related species to begin breeding, the water in the tank must be brought to between 82–88 °F (28–31 °C), with a pH level of 6-7 and moderate to low light. [6] X Research source Goldfish breed in spring. Lower the water temperature to 52 °F (11 °C). Then, when you are ready to breed them, gradually raise it 3 °F (1. 7 °C) per day until it reaches 72 °F (22 °C). If you have to make a significant adjustment to the water in the spawning tank, do it little by little. Water temperature, for instance, should only be raised or lowered 3-5 degrees over the course of about a week. Too drastic a change in too short a time may agitate or even harm the parent fish. [7] X Research source
In order for Discus and related species to begin breeding, the water in the tank must be brought to between 82–88 °F (28–31 °C), with a pH level of 6-7 and moderate to low light. [6] X Research source Goldfish breed in spring. Lower the water temperature to 52 °F (11 °C). Then, when you are ready to breed them, gradually raise it 3 °F (1. 7 °C) per day until it reaches 72 °F (22 °C). If you have to make a significant adjustment to the water in the spawning tank, do it little by little. Water temperature, for instance, should only be raised or lowered 3-5 degrees over the course of about a week. Too drastic a change in too short a time may agitate or even harm the parent fish. [7] X Research source
When you first lower the water level in the tank, leave it shallow for a few days so that the fish have time to get used to the difference. Then, gradually return the water to its original level over the course of about a week, using water that’s 2–3 °F (−17 – −16 °C) cooler than what’s already in the tank. [9] X Research source For a more convincing simulation, try dimming the lights in the room and switching a flashlight on and off near the tank to make “lightning. ”
Constructing the ideal physical environment for breeding to take place will largely be a matter of knowing how the fish choose a mate and lay their eggs. These structures will also provide a place for the female fish to deposit her eggs. [11] X Research source
Sponge filters are typically recommended for aquarium breeding. Using a less powerful filter may make it necessary to clean or replace the water in the tank more frequently (up to 15-20% of the total volume every 1-2 weeks, depending on how murky it is).
With the exception of a few nurturing species, it’s not uncommon for adult fish to devour their own eggs. If it’s not possible to set up a different tank for the fry, add an abundance of plants and other physical structures to give them a place to hide once they’re capable of swimming. [14] X Research source
Be sure to black out the sides that receive the most direct light exposure. Leave one of the larger sides uncovered for observation. You can even leave the tank completely covered with a sheet when you’re not feeding or checking on the fry.
Draw from the same source every time you refill the tank. It’s important that the new water have the same basic composition as the old.
Look for the foods and supplements you need at pet stores that sell specialty fish supplies. As always, do your homework to find out what foods are suitable for the fry of the species you’ve selected for breeding. Smaller species like tetras and rainbowfish, for example, won’t be able to handle commercially prepared foods so soon after hatching, and need to be fed liquid infusoria or similar supplements that they can digest easily. As the fry grow larger, they can graduate to more substantial live foods like brine shrimp and microworms.
