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If you're interested in breeding silver dollar fish, you'll need to learn how to identify the males and females of the species so you can provide a suitable mate for your fish. Male silver dollar fish tend to have an anal fin that is longer than females. The anal fin is usually tinted red on most males as well. Once you've identified the males and females of the species, you'll want to pair them up in equal proportions in your aquarium. However, it's generally best to add more than one fish to the tank and let the fish pair themselves up, rather than trying to mate a particular pair of fish. Mix four to six fish with equal proportions of male to female (for example, if using four fish you would have two of each; if using six fish, have three of each). Let the fish decide how they want to pair up and don't interfere. While some aquarium enthusiasts may be reluctant to provide silver dollar fish with aquatic plants, your fish will need some type of underwater plants during mating. These can even be artificial plants if you're worried about your fish eating the plants. Silver dollar fish tend to lay their eggs on or around underwater plants. If you're trying to breed your silver dollar fish, you'll need to ensure that you don't accidentally remove the eggs or hatched fry while cleaning your tank. Eggs hatch within about three days, and within a week the fry will begin to swim around inside the tank and attach themselves to the walls of the tank. Try to hold off on cleaning the tank for a few days until the eggs are hatched and the fry are visible. Avoid using tank vacuums to clean your aquarium while there are eggs or fry present. Instead, try to do partial water changes and be sure you can see the fry at all times.
Identify the sex of your fish. Pair up males and females. Ensure there are plants in the tank. Exercise caution when cleaning the tank.