Neon Sunset Platy (Xiphophorus variatus)

Choose the Neon Sunset Platy, a glowing variatus platy

The Neon Sunset Platy is an aquarium-bred colour form of the variatus platy, Xiphophorus variatus, a small, peaceful livebearer from Mexico. Our photographs show the sunset pattern that gives it its name: a golden yellow head and front body that warms to deep orange and then orange-red towards the tail. Over that colour the scales carry a pale, iridescent sheen, which is what the trade means by "neon", and the fins are clear with a blue tint and fine yellow rays. A small red patch marks the gill cover.

The variatus platy is a good choice for a UK fishkeeper. It is hardy, easy to feed and happy in the moderately hard to hard tap water found in many areas, and it tolerates cooler indoor water than most tropical community fish. OATA even lists it among the fish suitable for an unheated indoor aquarium.

Check the names on the label

Tell it apart from our other variatus platies

Seriously Fish notes that wild variatus platies are slimmer than the common platy, with a slightly longer dorsal fin, and that some commercial varieties were produced by crossing with swordtails or common platies. Our Sunset Variatus Platy shows the same yellow-to-red sunset body, but with yellow and orange-red fins; the Neon Sunset has the stronger sheen and blue-tinted fins. For a different look, compare the tall-finned Sunset Simpson Variatus Platy, the Orange Gold Variatus Platy and the multicoloured Hawaii Variatus Platy. All share the same care and will interbreed.

Know exactly what you receive

One purchase supplies one live Neon Sunset Platy of medium size, a young fish that has not finished growing. Sex is not chosen or guaranteed. Males are smaller and have a pointed, rod-like anal fin called the gonopodium; females are larger and rounder with a fan-shaped anal fin. Colour and sheen differ slightly from fish to fish and are often paler for a few days after the journey.

Decide how many to order

• Three fish: the smallest group OATA recommends, ideally one male and two females.
• Six fish: a more natural display with two females to each male.
• A mixed platy tank: combine with other variatus forms only if you are happy for them to interbreed.

Read our delivery and Live Arrival Guarantee information before you order and have the aquarium filtered and matured before the fish arrive.

Plan the aquarium around the adult size

OATA gives adult platies as 6–8 cm, and its unheated-aquarium guidance gives the same 6–8 cm for the variatus platy. Seriously Fish gives a maximum of 50 mm standard length, which is measured without the tail, and FishBase records 7.0 cm total length. Males stay smaller than females.

OATA asks for at least 45 litres for a small group of platies. Seriously Fish recommends a base of 60 × 30 cm, about 54 litres, and FishBase also gives a minimum aquarium length of 60 cm. Larger tanks give more stable temperature and water quality, as OATA points out, and they cope better with the fry that a mixed group will produce.

Run a three-step space check

1. Measure the base: aim for at least 60 cm long and 30 cm front to back.
2. Count adults, not youngsters: plan for fish of 6–8 cm.
3. Leave room for growth in numbers: check your plans in our stocking calculator and see our ideas for the best fish for a 60-litre tank.

Plant it like a weedy Mexican ditch

Seriously Fish describes the natural habitat as shallow, heavily vegetated streams, ponds, swamps, canals and ditches, often where algae and phytoplankton are abundant. FishBase adds warm springs, weedy canals and ditches. Plenty of plants therefore suit this fish well, and the algae that grow on them become part of its grazing.

Divide the tank by function

Leave a little algae on rocks and the back glass. Platies pick at it all day, and it is a natural supplement to the food you give.

Set hard water at a moderate temperature

The variatus platy needs alkaline, mineral-rich water, and it copes with a wider temperature range than many tropical fish. The sources agree on pH but differ on temperature and hardness, so here they are side by side.

Read the sources side by side

OATA's unheated-aquarium guidance says fish like this must only be kept in indoor aquaria. In a room that stays warm, the fish may manage without a heater; in a cold room or a house that cools sharply at night, a heater set at about 22°C keeps the water inside every source's range. Test your tap water first, compare it in our water matcher and read our water chemistry guide. Soft, acidic water does not suit this species.

Filter and maintain a growing population

Seriously Fish suggests a filter turning the water over four to five times an hour, about 215–270 litres per hour for a 54-litre tank, and a heater of roughly 50 W for a room near 20°C. Platies are small, but a breeding group grows fast, and the filter has to keep pace.

Follow a weekly routine

1. Test ammonia, nitrite, nitrate and pH at least once a week, as OATA advises.
2. Change 25% of the water at least weekly with dechlorinated water at the same temperature.
3. Siphon waste from the gravel and trim decaying plant leaves.
4. Rinse filter sponges in removed tank water, never under the tap.
5. Count fry and young fish so the tank never becomes overcrowded unnoticed.

Feed a plant-rich diet once a day

Seriously Fish describes the variatus platy as omnivorous, eating small bottom-living animals and detritus in the wild, and FishBase lists worms, crustaceans, insects and plant matter. In the aquarium it accepts frozen, live and dried foods. OATA recommends a quality flake or granule with a high algae content, fed once a day in an amount eaten within a few minutes, with occasional live or frozen foods.

Build one measured meal

• Staple: algae-rich or vegetable flake, crushed small enough for every fish.
• Variety: Daphnia, brine shrimp or bloodworm a few times a week, in place of part of the staple.
• Portion: what the group finishes in a few minutes; remove leftovers.
• Fry: Seriously Fish suggests feeding fry two to three times a day on powdered flake or brine shrimp nauplii.

Introduce the fish to a mature aquarium

Check before arrival that the filter is mature, ammonia and nitrite are zero and the water is at pH 7.0–8.0 and a steady temperature. Use OATA's floating-bag method: float the sealed bag for 10 minutes, add small amounts of tank water over up to 20 minutes, and release the fish without adding the bag water to your aquarium. Our guide on how to acclimatise new fish shows each stage.

Use a first-week checkpoint plan

Keep a balanced group with peaceful tank mates

Seriously Fish describes the variatus platy as peaceful and hardy and a good community fish, but warns that males can be relentless in their attention to females. OATA recommends at least three fish, with two females to each male. More females spread the attention, and plants give a female somewhere to rest.

Screen each companion

Check any mix with our tank mates tool. Browse all platy fish and livebearers, the platy category and our Xiphophorus variatus platies. Our variatus platy guide and platy care guide cover the group in more depth.

Breed platies or keep the numbers steady

Platies give birth to live young after internal fertilisation. Seriously Fish gives a gestation of around 4–7 weeks and says broods of over 100 fry are not uncommon; FishBase gives 24 days and up to 100 young, and OATA gives 24–30 days and 20–80 fry for platies and swordtails. The sources differ, but all agree that a healthy female can produce a large brood regularly.

Raise a brood

1. Plant densely: Seriously Fish recommends several females per male and dense planting.
2. Protect the fry: OATA suggests moving a heavily pregnant female into a breeding net, because adults eat fry.
3. Feed little and often: two to three small meals a day for the young.
4. Plan homes: decide in advance where surplus youngsters will go, and never release them.

If you want to keep a line looking the same, breed only within one colour form. Seriously Fish also asks keepers not to cross wild-type variatus with domestic forms.

Watch for problems early

OATA's warning signs for platies are clamped fins, flicking against objects, shimmying, hanging at the surface or sitting on the bottom, colour change, white spots or fluffy growths, lost fins or scales, a changed breathing rate and reduced appetite.

Pair each sign with an action

FishBase lists the variatus platy as a potential pest where it has been introduced, and Seriously Fish records feral populations in several countries. Unwanted fish should go back to a shop or another keeper, never into a pond or river.

Answer Neon Sunset Platy buying questions

What is a Neon Sunset Platy?

It is an aquarium-bred colour form of the variatus platy, Xiphophorus variatus, a small livebearer from the Atlantic slope of Mexico. Our photographs show the sunset pattern, golden yellow at the front shading to orange-red towards the tail, with an iridescent sheen on the scales and clear, blue-tinted fins with yellow rays. "Neon" is a trade name for that shine.

How is it different from a Sunset Variatus Platy?

Both are sunset forms of the same species with the same care. On our photographs the Neon Sunset has a stronger iridescent sheen and blue-tinted fins, while our Sunset Variatus Platy has yellow and orange-red fins. If you want the two to look alike in one group, keep one form.

How big does it grow?

OATA gives variatus platies 6–8 cm. Seriously Fish gives a maximum of 50 mm standard length, measured without the tail, and FishBase records 7.0 cm total length. Males stay smaller than females.

Can a Neon Sunset Platy live without a heater?

It is one of the few tropical community fish that tolerates cooler indoor water. OATA lists the variatus platy among fish for unheated indoor aquariums and gives 17–27°C, and FishBase gives 15–25°C. It must stay indoors, and a heater set at about 22°C keeps conditions steady in a cold room.

What size aquarium does it need?

OATA asks for at least 45 litres for a small group of platies. Seriously Fish recommends a base of 60 × 30 cm, about 54 litres, and FishBase gives a minimum aquarium length of 60 cm.

What water does it need?

Hard, alkaline water. Keep it at pH 7.0–8.0, where all three sources agree, and in moderately hard to hard water: Seriously Fish gives 14–30 dGH, FishBase 9–19 and OATA a softer 4–12°dH for platies in general. Zero ammonia and nitrite, and nitrate no more than 20 mg/l above tap water.

How many should I keep?

At least three, with two females to every male, as OATA advises. Seriously Fish warns that males can be relentless in their attention, so more females spreads the pressure.

Will it breed in my aquarium?

Almost certainly, if both sexes are present. Seriously Fish gives a gestation of around 4–7 weeks and says broods of over 100 fry are not uncommon; dense plants help some fry survive.

How many fish come with one purchase?

One live fish of medium size. Sex is not chosen or guaranteed, and colour varies a little from fish to fish.

Consult the care references

• Seriously Fish: Xiphophorus variatus — size, aquarium base, water values, distribution, habitat, diet, behaviour, gestation, brood size and hybrid strains of the variatus platy.
• FishBase: Xiphophorus variatus — maximum recorded length, subtropical temperature range, pH and hardness, distribution, gestation and brood size.
• OATA: How to look after swordtails & platies — UK trade-body guidance for platies and swordtails: adult sizes, tank volumes, water values, sex ratio, feeding, breeding, acclimatisation and health signs.
• OATA: How to pick and look after fish for an unheated aquarium — UK trade-body guidance listing the variatus platy among fish for unheated indoor aquariums, with its size and 17–27°C range.
• Tropical Fish Co delivery policy — current dispatch days and Live Arrival Guarantee terms.