Platy Coral Red (Xiphophorus maculatus coral)

Choose a coral-red platy for a peaceful community

Platy Coral Red is a coral-red aquarium colour form of Xiphophorus maculatus, a freshwater livebearer in the Poeciliidae family that reaches 4 cm. FishBase describes the wild species from warm springs, canals, ditches, creeks and swamps between Veracruz in Mexico and northern Belize. Wild fish feed on worms, crustaceans, insects and plant matter.

This is a small, generally peaceful fish suited to a planted community aquarium where its water requirements, social needs and future population can be planned in advance. The red colour is the defining trade feature, but choose it for the fit with your aquarium rather than colour alone. Browse the wider platy fish collection when comparing colour forms.

Choose the dispatch size

One purchase supplies one animal of the selected option. The size you select is the size supplied, not the adult size. Use the live size selector to make your choice, then plan the permanent aquarium around the adult measurements in the next section.

Sex is guaranteed only when the selected option explicitly states male or female. This Platy Coral Red listing has no sex-guaranteed option.

The gallery images are representative, based on reference photographs of this species, so colours can look slightly different from the live animal.

Plan the aquarium around adult measurements

Plan for an adult size of 4 cm. FishBase records a maximum of 4 cm total length for male or unsexed fish, while the Seriously Fish species profile separately lists 5 cm standard length. Use the 4 cm adult figure throughout the stocking plan and follow the stated aquarium footprint rather than trying to predict the exact final length of an individual fish.

Start with an aquarium at least 60 cm long. A 60 × 30 cm base and a typical 60 × 30 × 30 cm aquarium give approximately 54 litres. This footprint leaves room for planting, shelter and open swimming space while allowing the keeper to maintain the small social group recommended for platies. Increase the aquarium size when adding more fish or when other occupants place greater demands on space and filtration.

Use these long-term planning values

The routine water target is the overlap of the FishBase environmental record of 18–25°C, pH 7.0–8.0 and 9–19 dH and the Seriously Fish aquarium range of 20–26°C, pH 7.0–8.2 and 10–30 dGH. OATA’s platy and swordtail guidance applies to the wider group and gives 17–27°C, pH 7.0–8.0 and 4–12 dGH; its range narrows the working hardness target to 10–12 dGH.

Check whether this fish fits your aquarium

This fish is a sound choice when your aquarium can hold those values steadily, has a mature biological filter and can accommodate companions without crowding. Test your tap water before choosing it: repeatedly forcing unsuitable soft, acidic water towards the target creates a less dependable routine than selecting fish that naturally fit the water you can maintain.

Hold the water within the working range

Aim for 20–25°C, pH 7.0–8.0 and 10–12 dGH as the routine aquarium range. Seriously Fish warns that Xiphophorus maculatus will not thrive in soft, acidic water, so hardness and pH deserve the same attention as temperature. Stability within the range matters more than repeatedly adjusting the aquarium towards one exact number.

Test before changing anything

OATA recommends zero milligrams per litre ammonia, zero milligrams per litre nitrite and nitrate no more than 20 mg per litre above the normal tap-water level. Compare aquarium water with conditioned tap water rather than reading nitrate in isolation. The shop’s water chemistry guide explains what each test measures, while the water matcher helps compare your measured values with this fish’s target.

Use a consistent testing method and write down results. A sequence such as pH 7.6, 7.5 and 7.6 over several weeks shows a steadier aquarium than isolated readings taken with different methods. Test at least weekly and whenever behaviour, breathing, appetite or appearance changes. If the result differs sharply from the previous reading, repeat the test before making a major adjustment.

Treat replacement tap water with a conditioner that removes chlorine or chloramine before it enters the aquarium. Match the replacement water closely enough to prevent a sudden temperature change, then add it steadily. Do not compensate for poor water quality by making rapid pH or hardness swings: remove waste, restore the maintenance routine and correct the underlying cause.

Establish filtration before adding fish

A mature biological filter is essential before a Platy Coral Red enters the aquarium. The RSPCA explains that biological filtration supports bacteria that convert toxic ammonia first to toxic nitrite and then to the safer nitrate. A filter running for a few days is not automatically ready; use test results showing zero ammonia and zero nitrite before adding livestock.

For an aquarium of about 54 litres, Seriously Fish gives a turnover of four to five times the aquarium volume per hour and a filter rating of approximately 215–270 litres per hour. Treat the rating as a planning value rather than a promise of actual flow. Filter media, pipework, height and accumulated debris can reduce performance, so watch circulation and check the unit for blockages.

Build a dependable routine

1. Before livestock: mature the filter and confirm zero ammonia and zero nitrite.
2. When adding fish: increase the population slowly so the bacterial colony can respond to greater waste and feeding.
3. At least once a week: change 25% of the water, siphon accumulated solid waste and record the test results.
4. When flow falls: check the intake and rinse dirty filter media lightly in removed aquarium water.
5. During cleaning: do not run the filter media under the tap.

Do not replace every mature filter medium at the same time. Preserve as much established biological media as practical while removing blockages and debris. A clean-looking aquarium can still contain ammonia or nitrite, so appearance never replaces testing.

The larger the aquarium, the more water there is to dilute short-term changes, but volume does not remove the need for filtration or maintenance. Crowding or adding several fish quickly can overwhelm a previously stable filter. Prepare and mature a new system with the first tropical tank guide, then increase the population in measured stages rather than treating the aquarium’s stated volume as a stocking allowance.

Build cover and open swimming room

A planted aquarium suits this platy well. Seriously Fish notes that the species appreciates planted conditions, while OATA recommends gravel or sand and live plants where practical. Artificial plants and suitable ornaments can also create shelter, but every decoration should leave enough clear water for normal swimming.

Divide the footprint deliberately

Arrange the tank from the adult stocking plan backwards. Place taller planting and shelter around the edges, then retain an open route through the middle and front of the aquarium. Check that no ornament traps a fish and that broad leaves or artificial foliage do not block the filter intake.

Wild Xiphophorus maculatus occur in slow-moving canals, ditches and other weedy habitats, but the aquarium still needs effective circulation. Spread the filter return across the tank instead of directing one concentrated jet through the only open swimming area. The goal is steady water movement and reliable filtration alongside places where fish can move out of the strongest flow.

A roughly 54-litre aquarium can be heated with around 50 watts when the surrounding room is close to 20°C, according to the Seriously Fish planning example. Room temperature, aquarium position and equipment design affect the result, so select the heater by the manufacturer’s rating and confirm performance with a separate thermometer. Protect the 20–25°C routine range from cold draughts, direct heat and rapid daily swings.

Feed one measured meal each day

Platies are omnivorous. Wild Xiphophorus maculatus feed on worms, crustaceans, insects and plant matter, while aquarium guidance recommends a good-quality flake or granule with a high algae content. Small live or frozen foods such as daphnia, small bloodworm or tubifex can add variety. Seriously Fish also describes the species as accepting dried, frozen and live food.

Feed once a day and offer only what the fish can eat within a few minutes. Start with a small amount that all members of the group can reach. If food is still drifting through the aquarium after the feeding period, reduce the next portion. If one fish takes most of the food immediately, distribute the same modest meal across more than one point rather than increasing the total without checking consumption.

Use variety without losing portion control

Match particle size to the fish at the time of feeding. Smaller dispatch sizes need pieces they can take readily, while larger fish can handle larger flakes or granules. Crushing a suitable dried food changes particle size without changing the daily feeding rule.

Uneaten food breaks down and adds waste, placing extra demand on the biological filter. Remove obvious leftovers and review the next portion rather than allowing them to accumulate among plants or gravel. A rising nitrate trend, food remaining after several minutes or a dirty substrate all point towards reviewing the amount offered, the number of fish and the maintenance routine.

Do not use extra food as a colour guarantee. The supported goal is a balanced omnivorous diet, appropriate particle size and controlled daily portions. Observe whether every fish approaches food and eats; a sudden reduction in interest is a health or water-quality prompt rather than a reason to keep adding different foods.

Acclimatise over 20–30 minutes

Prepare the aquarium before the delivery window. Confirm that the filter is operating and ammonia and nitrite are both zero. Keep a thermometer and water tests ready so the aquarium can be checked before the fish’s introduction.

Follow the shop’s delivery and Live Arrival Guarantee policy when the parcel arrives. Film every delivery continuously from the sealed parcel as it is opened, keeping the fish inside the sealed bag visible before anything is disturbed. Float the bag for 20–30 minutes before releasing the fish, and never pour the bag water into the aquarium.

Work through the arrival in order

1. Receive the parcel: arrange for someone to be present because live fish must not be left unattended.
2. Start filming: begin with the parcel still sealed and the outer box visible.
3. Open continuously: keep filming as the parcel is opened and show the fish still inside the sealed bag.
4. Float the bag: float the bag for 20–30 minutes before releasing the fish.
5. Release carefully: move the fish into the aquarium and never pour the bag water into the aquarium.

Judge the first hours by changes rather than by expecting instant exploration. Transport and a new environment can alter behaviour, so look for a steady move towards normal swimming and responsiveness. Record anything unusual and test the aquarium water before assuming the cause.

During the first week, check the new fish at feeding time and at a quiet time each day. Confirm that it can reach food, is not being persistently displaced and does not remain at the surface or bottom. Test ammonia and nitrite after the addition because the filter’s bacterial population must adjust to the greater waste load.

If breathing, posture, colour, appetite or swimming deteriorates, test temperature, ammonia, nitrite, nitrate and pH and contact us with the results and a clear description of the change. Do not begin a disease treatment solely from one general symptom; water quality and social pressure should be checked first.

Use changes as early health signals

Learn the normal behaviour and appearance of each fish so a change is noticed early. OATA highlights swimming, colour, temperament, breathing, external appearance, body condition and feeding as useful observations. A single brief change may need watching; several changes together call for immediate water testing and a review of recent events.

Pair each sign with a first action

Use a simple weekly record containing temperature, pH, ammonia, nitrite, nitrate, water-change date and any behavioural change. The record makes trends visible: a fish losing interest in food as nitrate rises suggests a different first action from one being displaced only when tank mates feed.

Review recent changes whenever a problem appears. New fish, increased feeding, a blocked filter, replaced filter media or missed maintenance can all change the pressure on the biological system. Pause further additions while the cause is investigated.

Body condition also matters. Compare the fish with its own recent appearance rather than expecting every individual to have exactly the same outline. Look for a persistent increase or decrease in condition, damaged scales, bumps or ulcerated areas. Clear observations and water results are more useful than choosing treatment from colour or one isolated movement.

Keep a 25% water change at least once a week, with regular tests and filter checks, even when every fish looks well. Preventive routine protects the stable conditions this platy needs and gives you a dependable baseline when behaviour changes.

Plan a social group and future numbers

OATA recommends keeping at least three platies because they require companionship. Use about 54 litres with a 60 × 30 cm base as the starting species plan rather than reducing the aquarium to the wider group’s 45-litre figure. More fish require more volume, filtration capacity and open swimming room.

For a group known to contain both sexes, OATA recommends two females for each male, while Seriously Fish advises more females than males because male attention can be relentless. Build that ratio only from fish whose sex is already known. If the ratio cannot be planned, leave enough space and cover to respond to the group’s behaviour rather than assuming every combination will remain settled.

Account for livebearing before adding the group

Platies give birth to live young, and Seriously Fish notes that batches of fry can be continual when males and females live together. Treat potential fry as future occupants: they add feeding, waste and space demands even when the starting group fits comfortably. Dense planting creates cover, but it does not increase the aquarium’s biological capacity.

• Starting group: plan for at least three platies.
• Known mixed-sex group: keep more females than males; OATA’s working ratio is two females for each male.
• Larger group: increase aquarium volume and filtration rather than filling every open area.
• Fry appear: reassess total numbers, feeding and water quality before adding more fish.

Seriously Fish describes males as tolerating one another, but every community still needs observation. Watch whether all members use the aquarium, reach food and retain normal condition. Persistent pursuit or one fish spending more time hidden means the social arrangement needs review.

Do not estimate group capacity from fish length alone. Plants, ornaments, tank mates, filter performance and the possibility of young all affect how much usable space remains. A lightly occupied 60 × 30 cm aquarium gives more flexibility than one planned to its limit from the first day.

Screen every community by behaviour and water

Seriously Fish describes Xiphophorus maculatus as very peaceful and suitable with most community species. That is a starting point, not a universal tank-mate list. Assess each proposed combination by adult size, temperament, water requirements, feeding behaviour and the space left after every fish matures.

Require a pass on every check

A fish described as peaceful can still be a poor match if it needs soft, acidic water, a different temperature or a feeding method that leaves the platy unable to eat. The reverse also applies: shared water values do not resolve a behavioural mismatch. Require agreement on both water and behaviour.

Use adult needs rather than dispatch dimensions when comparing fish. The selected platy may arrive small, but the aquarium must still support its 4 cm adult size, social group and the mature size of every companion. Compare usable footprint after planting and decoration, not volume alone.

For a proposed mix with uncertain behaviour, contact us with the aquarium dimensions, measured water values, filter, existing species and their numbers. Honest uncertainty is better handled with a tank-specific assessment than by naming a companion as universally safe.

Introduce community members in measured stages

Add fish slowly so the biological filter and the existing social group can respond to each change. Before an introduction, test for zero ammonia and zero nitrite, confirm the 20–25°C temperature target and check that the aquarium still has open swimming space and shelter.

Review the match at three checkpoints

1. At release: confirm that the newcomer swims normally and is not immediately pursued or displaced.
2. At the next daily meal: watch whether it reaches food without one resident controlling every feeding point.
3. Across the first week: look for persistent hiding, damaged fins, erratic swimming, altered breathing or reduced condition.

If a problem appears, pause additional livestock and identify whether the cause is water quality, crowding, competition or social pressure. Test before changing the water chemistry. A good ammonia result does not rule out behavioural stress, and peaceful behaviour does not make unsuitable water safe.

Consider a proposed community that shares pH 7.0–8.0 but needs 26–28°C. It fails the temperature check because the shared routine extends beyond the platy’s 20–25°C target. A calm community that shares all three water ranges passes the initial screen, but it remains conditional on adult space, feeding access and observation after introduction.

Mixed-sex platy groups need another check. Where sexes are known, keep more females than males and use two females for each male as the OATA planning ratio. Continual fry can change a previously comfortable stocking level, so reassess total numbers before any further addition.

Do not respond to early tension by adding several more fish at once. More animals increase waste and may make the social picture harder to interpret. Make one measured stocking change, observe its effect and allow the aquarium routine to settle before deciding on the next step.

Answer the essential questions before choosing

How big does Platy Coral Red get?

Platy Coral Red reaches 4 cm using the FishBase maximum recorded length for male or unsexed fish. Plan the aquarium around this adult figure rather than the dispatch size.

What size aquarium does this platy need?

Plan at least a 60 × 30 cm aquarium base, approximately 54 litres for a 60 × 30 × 30 cm tank, with a mature filter, plants or other cover and open swimming room.

How many Platy Coral Red should I keep together?

OATA’s group guidance recommends at least three platies. Where a group is known to contain both sexes, use two females for each male and allow extra capacity for live young.

Is this fish suitable for beginners?

Yes, it can suit beginners who can provide a mature filtered aquarium and keep the pH above neutral. Maintain the routine target of pH 7.0–8.0 and avoid soft, acidic water.

What does Platy Coral Red eat?

Feed a quality flake or granule with a high algae content once daily, offering only what is eaten within a few minutes. Small live or frozen daphnia, bloodworm or tubifex can add variety.

What temperature and pH does this fish need?

Keep it at the FishBase, Seriously Fish and OATA overlap of 20–25°C, pH 7.0–8.0 and 10–12 dGH. Maintain zero ammonia and zero nitrite, and test the water at least weekly.

Is Platy Coral Red aggressive or likely to nip fins?

Seriously Fish describes this platy as very peaceful and says that even males tolerate one another. Monitor every community for pursuit, hiding, damaged fins or feeding competition.

Which fish can this fish live with?

Choose peaceful community species that share 20–25°C, pH 7.0–8.0 and 10–12 dGH and leave enough adult space. Screen temperament, feeding and filtration capacity before every introduction.

How does Platy Coral Red arrive alive in the UK?

Start filming the sealed parcel before it is opened and continue as it is opened, showing the fish still inside the sealed bag. Have someone present to receive it, float the bag for 20–30 minutes, then release the fish without pouring the bag water into the aquarium.

Use the reference library

• FishBase: Xiphophorus maculatus — accepted identity, family, wild distribution, environmental record, biology and recorded maximum length.
• Seriously Fish: Xiphophorus maculatus — aquarium footprint, water ranges, diet, behaviour and livebearing notes.
• OATA: How to look after platies and swordtails — wider-group guidance for water quality, companionship, feeding and maintenance.
• RSPCA aquarium environment guidance — biological filtration and the processing of ammonia, nitrite and nitrate.