The platy (Xiphophorus maculatus, X. variatus, Xiphophorus spp. hybrids) is one of the best options for beginner fishkeepers and a great stand-by for more advanced hobbyists. Their variety of colors is in the same realm as that of discus and cichlids of Lake Malawi. But they are hardy, small, and non-aggressive.
They are native from Belize through Mexico. They are native to warm, but not tropical waters of 18-25C (64-77F) making them a great option for tanks without heaters. Their native waters are naturally hard and alkaline with a pH ranging from neutral up to about 8.0. They are hardy and can thrive in water with a pH outside this range as long as it is stable and water quality is high.
Maximum size may be listed as less in some sources, but I have had them hit about 2.5”. This was in a relatively short amount of time and if kept for many years they may even be able to exceed this.
They will actively accept most foods. This can range from live, frozen, dried, flakes, and even small pellets. Mine are fed New Life Spectrum exclusively, as are all my fish.
They are livebearers and require very little to breed. Ideal sex ratio is at least two females per male, but many more females than this can be successfully bred with a single male. Sexing is simple. Males have a gonopodium. This is what is used to deliver the sperm to the females. To differentiate simply look at the anal fin (last fin on the bottom of the fish before the tail). In females it will be fan-shaped, in males it will be rod-shaped. High water quality is important for proper sex ratios in the offspring. In lower water quality (higher nitrates) more males will be produced. This is a natural mechanism to slow down the rate of reproduction in the species when times are hard or the population is too dense. Sense it is ideal to have at least two females per male, most people do not want any additional males, so producing more is not a good idea. Males will be aggressive with each other and females if not enough females are present.
Potential tank mates include many of the cool water species such as danios, but like danios since they are hardy enough to do well or even thrive in tropical temperature water, they can also do well with many community fish such as tetras and barbs. Platies can be a little nippy so slow moving species and long-finned varieties should be avoided. As with any fish, fish large enough to eat them should also be avoided.
Aquarist since 1995
Biologist and Published Author in Multiple Aquarium Magazines
Owner: Aquarium Maintenance Company
Advanced Aquarium Concepts:
Articles about many aspects of aquarium care.