Platy Fish: Care, Tank Size, Group Size and Breeding

Platies are small, peaceful livebearers in the genus Xiphophorus, the same genus as swordtails. Two species are sold, the southern platy and the variatus platy, but most platies in shops are hybrids of the two (Wikipedia). Both reach at most 7.0 cm (2.8 in).

Colour varieties are sold under trade names: AZ Gardens lists Mickey Mouse, bumblebee, panda, red tiger, green lantern, neon blue wag, salt and pepper, redtail dalmatian and others. Wikipedia lists red, yellow, orange, blue, rainbow and white forms.

Male or female? Look at the anal fin. In males it is modified into a pointed rod, the gonopodium, used to fertilise females; females have a normal fan-shaped anal fin (Wikipedia). Photograph the fish side-on with the belly visible if you want the app to help with sexing and variety.

Keep platies as a group, with more females than males. Sciencegal Aquatics says platies do better in a group, and its author keeps six (two high fin, two Mickey Mouse and two neon wagtail) in a 20-gallon long tank. AZ Gardens recommends two females for every male, so that no single female is harassed.

Tank size advice varies. Sciencegal Aquatics gives a 10-gallon minimum; AZ Gardens says platies suit aquariums of 2.5 to 20 gallons but adds that larger tanks reduce stress. Because a female can drop 20 to 50 fry about once a month (Wikipedia), a small group can outgrow a small tank quickly, so we suggest planning around the larger figure.

Yes, they are among the easier aquarium fish, as long as the water suits them. Sciencegal Aquatics describes them as peaceful, active swimmers that use every level of the tank and do not nip fins.

The water ranges given by different sources overlap but do not match, so aim for the middle: Wikipedia gives 72-82°F, pH 6.8-8.0 and 10-28 dGH; Sciencegal Aquatics gives 70-82°F and pH 7.0-8.2 with harder water; AZ Gardens gives 65-79°F, pH 7-8.5 and 10-25 dH. The range all three agree on is 72-79°F, pH 7.0-8.0 and 10-25 degrees of hardness.

Diet: platies are omnivores; Sciencegal Aquatics recommends high-quality, protein-rich flakes or granules plus frozen or live bloodworms and brine shrimp, and notes they graze on algae in the tank.

Tank mates: other peaceful fish that do not nip fins and cannot fit a platy in their mouth. Sciencegal Aquatics names Kerri tetras, long-finned danios, Corydoras catfish and harlequin rasboras.

Wikipedia gives 20 to 50 fry at once, as often as once a month, and warns that the adults may eat their own fry. Sciencegal Aquatics reports broods ranging from only a few to more than a hundred, about every 30 days, with females breeding especially freely when kept outdoors. Platies are livebearers: the young are born alive rather than hatching from eggs laid in the tank.

Neither is better in general; they suit different tanks. Both are livebearers, but the numbers differ:

• Size: platies reach 7.0 cm (Wikipedia); the short-finned molly, Poecilia sphenops, reaches 8.4 cm standard length or 10 cm total length (Wikipedia).
• Brood: platies drop 20 to 50 fry (Wikipedia); the molly can produce up to 150 young after a month-long gestation (Wikipedia).
• Water: the molly lives in both freshwater and brackish habitats in the wild (Wikipedia); platies are freshwater fish.

For a smaller tank, the platy's smaller size and smaller broods are easier to manage. Mollies need more room and produce more young.

Sale prices on AZ Gardens on 25 September 2026: assorted platy $5.59 (was $8.99); Mickey Mouse varieties, green lantern, neon blue wag, red wag, salt and pepper and redtail dalmatian $5.88 each (was $8.99); bumblebee, panda and red tiger platies $6.88 each (was $9.99); variatus varieties $3.88 to $5.88. Prices change, and shipping live fish usually adds to the cost.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Every number names the organisation it comes from, and where sources disagree we say so instead of picking one silently. Prices and rules are given with the date we checked them (25 September 2026); they change, so confirm before you rely on them. If you find an error, tell us and we will correct it.