How big does Platy get?

Platy reaches an adult standard length of 2.5–5 cm (excluding the caudal fin). Size the tank for that, not for the juvenile you bring home — the difference is often several times over, and upgrading later costs more than buying once.

What water does Platy need?

22–28 °C, pH 7–8.2, 10–20 dGH, 4–12 dKH. At 6 °C wide it is one of the more forgiving ranges.

What is the smallest tank for Platy?

At least 40 L, and no shorter than 50 cm. That is the floor for long-term keeping, not for short-term survival: volume buys water stability and length buys swimming room, and neither substitutes for the other. It is a schooling fish: keep at least 3 together. Fewer than that and it hides, loses colour, and aggression has nowhere to spread.

What is Platy like to keep?

Temperament: peaceful. Difficulty: beginner. It occupies the middle and is omnivore. With plants it is "Leaves plants alone".

Can Platy be kept with its most common tank mate?

The checker returns "Can be kept together". Platy and Guppy is a well-established pairing. Individual fish still differ; the record says "usually fine", not "guaranteed".

G-01 / 02Freshwater

Platy月光鱼

Xiphophorus maculatus · Poeciliidae

Mellow colors and hard-water tolerance make it the easiest poeciliid for hard tap water.

Illustration to come

G-01 / 02 · Platy Xiphophorus maculatus

SpecificationsFish atlas

Name: 月光鱼
Scientific name: Xiphophorus maculatus
Family: Poeciliidae
Origin: Central America (southern Mexico, Guatemala, Belize)
Adult size: 2.5–5 cm
Temperament: Peaceful
Diet: Omnivore
Water level: Middle
Level: Beginner
School size: ≥ 3
Min. tank: 40 L
Min. length: 50 cm
Plant safe: Leaves plants alone

Water requirementsFreshwater

Temp.22–28 °C

pH7–8.2

Hardness10–20 dGH

Alkalinity4–12 dKH

Units: temperature in °C, hardness in German degrees (dGH / dKH), marine salinity as specific gravity at 25 °C, volume in litres. These are the values recorded for the species and do not follow the site unit switcher.

Keeping notes

1Thrives long term in alkaline hard water and handles hard tap water better than tetras do.
2Gestation runs about four weeks and the belly squares off before birth; dense plants let the fry hide.
3Omnivorous with a plant lean: blanched spinach or spirulina beside flakes reduces nipping of soft shoots.
4A group in a tank 60 cm or longer does best; males display at each other but rarely injure one another.

Check a tank mate

Jump straight to the verdict for Platy against this one — no need to pick it again.

Frequently asked questions

How big does Platy get?: Platy reaches an adult standard length of 2.5–5 cm (excluding the caudal fin). Size the tank for that, not for the juvenile you bring home — the difference is often several times over, and upgrading later costs more than buying once.
What water does Platy need?: 22–28 °C, pH 7–8.2, 10–20 dGH, 4–12 dKH. At 6 °C wide it is one of the more forgiving ranges.
What is the smallest tank for Platy?: At least 40 L, and no shorter than 50 cm. That is the floor for long-term keeping, not for short-term survival: volume buys water stability and length buys swimming room, and neither substitutes for the other. It is a schooling fish: keep at least 3 together. Fewer than that and it hides, loses colour, and aggression has nowhere to spread.
What is Platy like to keep?: Temperament: peaceful. Difficulty: beginner. It occupies the middle and is omnivore. With plants it is "Leaves plants alone".
Can Platy be kept with its most common tank mate?: The checker returns "Can be kept together". Platy and Guppy is a well-established pairing. Individual fish still differ; the record says "usually fine", not "guaranteed".