Breeding Platies in Aquariums

One of the most popular fish in the aquarium hobby is the Platy, they are often the first choice for novice fish keepers as they have a great reputation for being hardy fish and they are very undemanding. They do have needs however and the most important need is to keep the water quality high in the tank, this applies to all species of fish not just the more delicate species. Often 1 or 2 specimens are added to the tank but they are in fact a social fish and do better in small groups of 5 to 6 specimens, they do not shoal like tetras for example but they do enjoy each others company.

They are an excellent community fish and will do well with most other species that require the same water parameters and they are available in a variety of colour variations. The most popular varieties available are Mickey Mouse, High Fin, Gold Comet.

Platys are live bearers and as such are often the first species of fish that novice keepers will attempt to breed but they are also bred by many experienced keepers as well due to their high popularity and wide market around the world. They will often produce young without the keeper even realising but the fry are lost as they can be eaten by other tank mates or just not receiving enough food initially to give them the strength to develop into adults.

Setting up a Platy Breeding Tank:-

Platys require hard, alkaline water, they do not do well in soft and acidic water so always remember this when setting up your tank. It is best to use a smaller tank for breeding as this reduces the volume of water required when performing the water changes and also reduces the amount of tank maintenance. A 10 gallon tank is large enough for this project and as I always do with breeding tanks it is best to use an air driven sponge filter for the filtration. This will prevent any fry from being sucked up filter intakes and cleaning the filter is very quick, it only takes a couple of minutes to squeeze the sponge in aged tank water to remove any debris. Fill the tank with water and set a heater to 24 deg C, leave the tank to settle for a few days before adding the selected fish to it. I find the best results when there are an equal number of males to females in the tank, other keepers find it best to keep more females than males. Finding out which is best for you will come with experience. The Platy is a very easy fish to sex, check the anal fin, with the females it will appear normal but the males have developed their anal fin into a tube called a Gonopodium which is used for transferring the sperm to the female. Once the fish are added to the tank give them a few hours to explore and settle down before you attempt to offer them any food. Keep the tank clean at all times and perform 25% water changes on a weekly basis to keep the water quality high. When you feed the fish offer them high quality flake and some live or frozen foods, I found the easiest was to supply them with frozen brine shrimp or frozen blood worms, this will ensure that the females will supply you with strong and healthy fry. The males will chase the females when they are ready to mate and sometimes this can look to be a bit tense but is perfectly normal, often males will compete against each other for the female’s attention but they will sort themselves out and the females will fatten up once mating has taken place. Pregnant females are easy to see as they will develop a dark “gravid” spot just in front of their anal fin, the spot is actually the eyes of the fry forming inside the female.

When the female looks really fat to the point of it looking painful you know she is about to give birth, this is a critical time as often newly born fry fall victim to the adult fish and get eaten. You now have two choices, either move the female into another tank or place her inside a breeder net in the same tank. I prefer to move the female as I do believe that breeder nets place stress on the female and she could abort the young but the method used is personal choice. The female produces a hormone 12 hours after giving birth which takes away any hunger that she has, this is natures way of protecting the young.

Rearing the fry

Breeder nets are fine for protecting the fry in the first few weeks so gently syphon them out of the tank and place them in the net. Normally female Platys will produce up to 30 young with each batch so there are quite a few to seek out and care for. They will accept the same diet as their parents from birth but if you are giving them quality flake food rub it in your fingers first to crush it slightly, this will make it easier for the fry to digest. They should be fed small meals 2-3 times per day, this will guarantee that all of the food will get eaten, uneaten food left in the tank will soon pollute the water.

After 1-2 months the fry should have reached 1” in size, it is now safe for these to go back into the tank with their parents.

It is possible for the females to store sperm ready for their next batch of young, do not be surprised if they give birth without you being ready for them. They normally produce young once a month and a regular pattern will soon emerge once yo get to know your fish. Keeping the water quality high and offering the fish quality food will increase your chances of successful breeding, selecting the best quality fish initially is also a must, weak and sick fish will produce sickly young.