At What Age Can a Fish Mate?

Fish are kept by many individuals as pets in ponds or aquariums. If you have fish long enough, you may want them to mate, or they may do so on their own. Every species of fish is capable of mating at different times, and when they mate depends on their health as well as the overall health of the pond or aquarium they are kept in.

  1. Goldfish

    • Many people are surprised to find that their goldfish don't wait long after they are born to start mating. Goldfish are able to mate at any age and will mate at any time of the year, as long as they are healthy. Goldfish are unlike a lot of other fish in that they will mate with other breeds of fish, such as koi.

    Koi

    • Although koi and goldfish are often kept in the same aquariums and ponds, koi do not start mating as early as goldfish. In fact, a koi needs to be three years old before it is capable of producing offspring. Then they will spawn once or twice a year, usually prompted by temperature changes in the water.

    Guppies

    • Guppies are more like goldfish in that they begin mating early. Most males begin to show an interest in mating between three and six weeks of age. Male guppies will mate repeatedly whenever a new female is put into the tank and with females already in the tank. Female guppies are typically between three and four months before they mate. Females that have not mated previously and are put into the tank usually cause a flurry of mating within minutes or hours.

    Betta

    • For bettas to mate successfully, you must consider age. Males reach sexual maturity a bit later than females, so it is not advisable to mate them before they are three to four months old and have a body length of at least one inch. The males will start showing interest before this time, but it is important to wait until all of their reproductive organs are fully formed. Females will be ready to mate at around three months.

    Clownfish

    • Clownfish should be purchased in pairs; they are very loyal to their mates. When you have a pair, they will likely begin to spawn after six months. You will notice that males are ready to mate when they begin chasing and nipping at the fins of the females. Interestingly, males can turn into females if a mating female is sick or unavailable.