Platy Berlin (Xiphophorus maculatus berlin)

Meet a peaceful livebearer for harder water

The Platy Berlin (Xiphophorus maculatus) is a freshwater poeciliid livebearer from the species’ native range between Ciudad Veracruz in Mexico and northern Belize. FishBase records a maximum length of 4 cm total length for male or unsexed fish. Its peaceful behaviour, compact size and straightforward feeding make it suitable for beginners who can provide neutral-to-alkaline, moderately hard water.

Keep this platy at 20–25°C, pH 7.0–8.0 and 10–12 dGH. These routine aquarium values are the overlap of FishBase’s recorded environment, the Seriously Fish species profile and OATA’s platy guidance. OATA’s figures are group guidance rather than a species-specific optimum. The narrow hardness overlap matters: Seriously Fish warns that X. maculatus will not thrive in soft, acidic water.

Start with the decisive requirements

• Adult planning size: 4 cm, using the FishBase maximum for male or unsexed fish.
• Aquarium footprint: at least 60 × 30 cm, as in the Seriously Fish example of a 60 × 30 × 30 cm aquarium holding approximately 54 litres.
• Social plan: OATA suggests at least three platies, with two females to each male in a mixed-sex group.
• Temperament: Seriously Fish describes the species as very peaceful and able to live with most community species; check each companion’s water and space needs first.

A planted, filtered aquarium with open swimming room suits its natural pattern of using slow-moving, weedy water. FishBase records wild adults in warm springs, canals, ditches, creeks and swamps, often around silt and weedy banks. Recreate the useful features rather than the silt: plants and shelter give cover, while clean open areas leave room to swim and feed.

Choose the dispatch grade without confusing it with adult size

Each purchase supplies one live Platy Berlin. Use the live size selector to choose the 3 cm dispatch grade. The size you select is the size supplied, not the adult size. Plan the permanent aquarium around the recorded 4 cm adult maximum and the full social group rather than around the fish’s length on arrival.

Sex is guaranteed only when the selected option explicitly states male or female. This Platy Berlin listing has no sex-guaranteed option. Do not base a mixed-sex ratio on assumed sex; assess the group’s composition before adding further fish. OATA’s suggested ratio is two females to each male, while Seriously Fish also advises keeping more females than males because male attention can be relentless.

The Berlin name identifies the aquarium colour form within Xiphophorus maculatus. Expect individual fish to vary in the exact pattern and intensity of their colouring. The gallery images are representative, based on reference photographs of this species, so colours can look slightly different from the live animal.

Make the purchase decision in the right order

1. Measure the aquarium’s base and confirm that it is at least 60 × 30 cm.
2. Test temperature, pH and general hardness against 20–25°C, pH 7.0–8.0 and 10–12 dGH.
3. Allow space for at least three platies and for any peaceful community fish already present.
4. Check that the biological filter is mature and that ammonia and nitrite are both zero before introducing the fish.
5. Choose the 3 cm dispatch grade from the live selector only after the permanent care plan works.

If you are comparing colours within the same group, browse the current platy fish collection. Treat colour as the final choice after water chemistry, aquarium footprint and group composition have been settled.

Check whether this platy fits your aquarium

This is a strong beginner choice when the aquarium is filtered, mature and kept above neutral pH. Seriously Fish calls Xiphophorus maculatus one of the best beginner species as long as pH remains above neutral, while OATA describes platies as generally peaceful and easy to keep. Ease of feeding does not remove the need to test hardness: soft, acidic water is a poor match even when the temperature looks suitable.

Use a simple pass-or-pause check

Pass: the aquarium has the required footprint, the filter is mature, tests show zero ammonia and zero nitrite, and the routine water values can remain within the stated range. There is enough capacity for the complete group as well as every existing fish.

Pause: the tap water is soft or acidic, the aquarium is still cycling, the planned group would crowd the footprint, or the existing fish need different water. Correct the setup before adding livestock rather than relying on gradual adjustment after introduction.

A larger aquarium gives more room for a group and generally holds temperature and water quality more steadily. Volume alone is not the whole decision, however: retain the 60 × 30 cm minimum base so the fish have practical swimming and feeding space.

Plan the aquarium around the adult size

Use 4 cm as the adult planning size for this offer. FishBase records that maximum for male or unsexed Xiphophorus maculatus. Seriously Fish lists 5 cm standard length, so allow spare capacity rather than treating the smaller figure as a reason to crowd the aquarium. Females grow larger than males, so retain spare capacity while planning around the 4 cm adult figure.

Provide an aquarium base of at least 60 × 30 cm. Seriously Fish illustrates that footprint with a 60 × 30 × 30 cm aquarium of approximately 54 litres. Both dimensions matter: a tall aquarium with less base area is not an equivalent substitute because it does not provide the same horizontal room.

Work through the space calculation

• One fish: platies require companionship, so plan the permanent home for a group rather than a single specimen.
• A small group: begin with the 60 × 30 cm base and approximately 54 litres stated for the species.
• A larger group: increase volume and usable swimming space. OATA advises that more groups require more volume.
• An established community: count every resident fish when judging capacity; the platies’ minimum footprint does not reserve space for unrelated tankmates.

The aquarium should combine cover with unobstructed swimming room. Live plants are especially useful because Seriously Fish says the species appreciates a planted aquarium. OATA recommends aquarium gravel or sand, plants or suitable ornaments for shelter, and open space for swimming. Place dense planting around the back or sides and leave accessible open areas where the group can move and take food without crowding.

Never treat the 3 cm dispatch grade as a temporary aquarium standard. The biological load increases with feeding and growth, and a social group adds waste from the beginning. Set up the adult aquarium first so filtration, water chemistry and group capacity are already settled when the fish arrives.

Hold the water inside the shared care range

Keep the aquarium at 20–25°C, pH 7.0–8.0 and 10–12 dGH. This is the shared overlap of FishBase, Seriously Fish and OATA guidance, so it remains inside every named range. Aim for steady readings within that overlap rather than moving between its extremes.

Set each value deliberately

• Temperature: maintain 20–25°C. Position the thermometer where it can be read easily and use repeated readings to identify drift.
• pH: maintain 7.0–8.0. Seriously Fish specifically warns that the species will not thrive in soft, acidic water.
• General hardness: maintain 10–12 dGH. Test this value rather than judging hardness from pH alone.
• Ammonia and nitrite: keep both at zero mg per litre.
• Nitrate: OATA advises that it should not exceed 20 mg per litre above the normal tap-water level.

Test the source water as well as the aquarium. A tank reading makes more sense when you know whether the tap water begins inside the target range and how it changes after treatment. Our water chemistry guide explains what the main tests measure, while the water matcher lets you compare measured values with the care range.

If the source water is soft or below pH 7.0, pause the purchase plan. This species needs moderately hard or harder water and is not a good choice for a naturally soft, acidic setup. Choose livestock that matches the water you can maintain consistently rather than forcing repeated large adjustments.

Test at least weekly and whenever behaviour, breathing, colour or appetite changes. Record the results so a rising nitrate level or movement in pH can be recognised before it becomes a persistent problem. Treat replacement tap water with a conditioner that removes chlorine or chloramine before adding it to the aquarium.

Build a mature, filtered and planted home

Run a well-established biological filter before adding the Platy Berlin. The RSPCA explains that fish release toxic ammonia, which filter bacteria convert first to toxic nitrite and then to safer nitrate. A filter therefore needs time to develop its bacterial population before it receives the waste from a social group.

If this is your first setup, follow the steps in our first tropical aquarium guide and confirm zero ammonia and zero nitrite before introducing fish. OATA warns that adding livestock too quickly can overwhelm the bacteria, producing new tank syndrome and unhealthy ammonia or nitrite levels.

Match the equipment to the 54-litre example

• Filter flow: Seriously Fish recommends turnover of four to five times the aquarium volume each hour. For its approximately 54-litre example, that means a filter rated around 215–270 litres per hour.
• Heating: the same profile estimates roughly 50 W to heat a 54-litre aquarium in a room around 20°C; set the heater to hold 20–25°C.
• Substrate: use aquarium gravel or sand as the base of the layout.
• Cover: live plants are preferred; when live plants are not used, add plastic plants and suitable ornaments for shelter.
• Open room: retain clear swimming and feeding areas instead of filling every part of the footprint.

Place the filter outlet so water circulates through the aquarium without turning the whole footprint into a forceful current. FishBase associates wild adults with typically slow-moving habitats, while the aquarium still needs enough circulation to carry waste to the filter and prevent stagnant areas.

Check that decorations are stable and that the group can move between cover and open water. A planted edge with a clear centre is one workable arrangement, but the decisive outcome is usable shelter plus unobstructed room. Inspect the filter regularly for reduced flow or blockage because the rated turnover only helps while water can pass through the media.

Feed an omnivorous diet in controlled portions

Feed a good-quality flake or granule with a high algae content as the routine dried food, then add small live or frozen foods such as daphnia, small bloodworm or tubifex for variety. FishBase records that wild Xiphophorus maculatus eat worms, crustaceans, insects and plant matter, so the aquarium diet should include both animal and plant-based components.

OATA advises offering platies only what they can finish within a few minutes, once a day. Seriously Fish also describes the species as unfussy and accepting most live, frozen and dried foods, but an easy appetite is not a reason to increase the portion.

Use the fish and the aquarium as feedback

• Food remains after a few minutes: reduce the next portion and remove uneaten material before it breaks down.
• One fish misses food: spread a small portion across more than one feeding point so peaceful group members can reach it.
• Body condition falls: check whether the fish is eating, then test water quality and observe for other changes.
• Nitrate rises or waste accumulates: review the portion before adding more food types.
• The group finishes instantly: do not assume the portion was inadequate; use body condition and water quality over time rather than feeding excitement alone.

Alternate suitable foods across the routine rather than mixing a large quantity into every meal. A dried staple supplies consistency, while small live or frozen items reflect the invertebrate component of the recorded diet. Use foods small enough for the platy to take cleanly.

Overfeeding turns uneaten food into waste, which adds pressure to the biological filter and can raise ammonia, nitrite or nitrate. Feeding and filtration are therefore one care decision: the correct portion is the amount the group consumes promptly while maintaining stable body condition and clean water.

Maintain water quality and act on changes

Carry out a 25% partial water change at least once every week. Use a siphon to remove solid waste from the substrate where needed.

Treat replacement water with a tap-water conditioner before it enters the aquarium. Match it carefully enough to avoid an abrupt temperature change, then refill without disturbing the fish or substrate more than necessary. Test ammonia and nitrite at least weekly and keep both at zero.

Protect the biological filter

1. Check the filter for blockage or reduced flow during routine maintenance.
2. Remove aquarium water as part of the scheduled partial water change.
3. If the media needs cleaning, rinse it lightly in that removed aquarium water.
4. Do not run it under the tap because chlorine or chloramine may kill the beneficial bacteria established in the media.
5. Return the media and confirm that normal circulation resumes.

Observe the group while feeding and during ordinary swimming. Healthy fish should have clear, bright eyes, intact scales and undamaged fins. Watch for hanging at the surface, sitting on the bottom, erratic swimming, darker or paler colour, increased hiding, altered aggression, faster or slower gill movement, white spots, fluffy growths, damaged fins or scales, changing body condition, or reduced interest in food.

If something changes, test temperature, pH, hardness, ammonia, nitrite and nitrate before making several adjustments at once. Correct a measurable water-quality problem promptly and observe whether normal behaviour returns. Separate a fish if continued chasing or injury creates an immediate welfare problem. If you remain concerned about the fish’s health after checking the water, seek advice from your aquarium retailer.

Keep a simple weekly record of test results, water changes, feeding response and visible condition. A record turns an isolated observation into a useful trend and helps distinguish a one-off disturbance from a developing aquarium problem.

Follow the arrival and acclimatisation steps in order

Be ready to receive the parcel in person. Live fish cannot be left unattended, and the Live Arrival Guarantee requires someone to receive the parcel and to open and inspect it on the day it arrives. Our delivery and Live Arrival Guarantee policy explains the current claim requirements and arrival procedure.

Use this arrival sequence

1. Receive the parcel in person.
2. Start a continuous unboxing video while the parcel is still sealed and the outer box is visible.
3. Open the parcel in the same continuous take and show the fish while it remains inside the sealed bag.
4. Inspect the fish before anything is disturbed.
5. Float the bag for 20–30 minutes before releasing the fish.
6. Do not pour the bag water into the aquarium.

Film every delivery from the sealed parcel onward. A short continuous unboxing video and the order number are needed for a Live Arrival Guarantee claim, so report any problem on the day the fish arrives. Keep the fish in the sealed bag while its condition is shown.

The fish is hand-packed in an oxygenated bag inside an insulated box, with a heat pack when the weather calls for it. A licensed live-animal courier carries the parcel, and tracking information is sent by email so someone can be present to receive it.

Prepare the aquarium before opening the parcel

OATA advises checking that ammonia and nitrite are zero before any fish is introduced. Confirm the aquarium is within 20–25°C, pH 7.0–8.0 and 10–12 dGH before delivery day, rather than trying to correct unsuitable water while the fish waits in its bag.

Add fish gradually because the filter’s bacterial population must adjust as livestock and feeding increase. During the first week, check feeding response, swimming, breathing, colour and interaction with the group while continuing the normal testing routine.

Plan the group before adding more platies

Keep companionship at the centre of the stocking plan. OATA suggests at least three platies and recommends two females to each male to reduce stress on females and other inhabitants. More can be kept when the same ratio and the aquarium’s capacity are maintained.

Turn the ratio into a practical plan

Seriously Fish describes males as tolerant of one another, but it also warns that male attention towards females can be relentless. More females spread that attention. Dense planting creates visual cover, although plants do not replace the need for an appropriate ratio and sufficient space.

Mixed-sex groups will produce continual batches of fry, because this livebearer breeds readily in the community aquarium. Include those fry in the capacity decision before combining males and females.

Check ammonia and nitrite after an increase in stocking or feeding. OATA explains that the beneficial bacteria must increase as more fish and more food add waste. Additions made too quickly can produce new tank syndrome even when the aquarium was stable with its previous population.

The social recommendation does not turn every platy into an interchangeable purchase. Group composition, total capacity and water chemistry must all work together. If one of those conditions fails, pause further additions until the aquarium can support the intended group.

Screen every community companion before mixing

Seriously Fish describes Xiphophorus maculatus as very peaceful and suitable with most community species. Treat “most community species” as a screening rule, not a universal tank-mate list: every companion must share the aquarium’s water, space and behavioural conditions.

Apply four checks to every proposed companion

1. Water: it must be comfortable at 20–25°C, pH 7.0–8.0 and 10–12 dGH.
2. Space: the aquarium must exceed the Platy Berlin’s 60 × 30 cm minimum whenever the combined population requires more room.
3. Behaviour: choose peaceful community fish and watch for persistent chasing, hiding, missed feeding or damaged fins after introduction.
4. Biological capacity: maintain zero ammonia and zero nitrite as stocking and feeding increase.

Compatibility beyond the description “most community species” remains a case-by-case decision. Do not assume that a familiar community label settles hardness, footprint or group capacity. Compare the requirements of each intended fish and use the narrower shared range.

Observe a new combination particularly closely during feeding and in the first week. Separate affected fish if chasing is persistent, a fish cannot reach food, fins become damaged or hiding replaces normal swimming. Test water at the same time because poor water quality can accompany behavioural changes and needs its own correction.

Get direct answers to common Platy Berlin questions

How big does Platy Berlin get?

Platy Berlin reaches a recorded maximum of 4 cm total length for male or unsexed fish, according to FishBase. Plan its permanent aquarium and group around that adult figure, not the 3 cm dispatch size.

What size aquarium does Platy Berlin need?

Provide a base of at least 60 × 30 cm. Seriously Fish illustrates this as a 60 × 30 × 30 cm aquarium of approximately 54 litres; increase the space when the total group or community requires it.

How many Platy Berlin should I keep together?

OATA suggests at least three platies. For a mixed-sex group, use two females to each male and maintain that ratio if the group becomes larger.

Is Platy Berlin suitable for beginners?

Yes. Seriously Fish describes the species as one of the best beginner fish when pH remains above neutral; keep it in mature, filtered water at pH 7.0–8.0 and 10–12 dGH.

What does Platy Berlin eat?

Feed a quality flake or granule with a high algae content, plus small live or frozen foods such as daphnia, small bloodworm or tubifex. Offer only what it eats within a few minutes, once a day.

What temperature and pH does this fish need?

Keep it at 20–25°C, pH 7.0–8.0 and 10–12 dGH. These values are the overlap of FishBase, Seriously Fish and OATA guidance.

Is this fish aggressive or likely to nip fins?

Seriously Fish describes it as very peaceful and says even males tolerate one another. Watch every new combination and separate affected fish if persistent chasing or fin damage occurs.

Which fish can it live with?

It can live with other platies in a planned group and with most peaceful community species whose water and space needs match. Use caution with large swordtails because OATA says they may chase timid tankmates.

How does this fish arrive alive in the UK?

Start filming while the parcel is still sealed, before opening it or floating the bag. The fish is packed in an oxygenated bag inside an insulated box and carried by a licensed live-animal courier; receive it in person, show it in the sealed bag, then float the bag for 20–30 minutes before release.

Check the public identity and care references

• FishBase: Xiphophorus maculatus — taxonomy, distribution, recorded environment, wild diet and maximum length.
• Seriously Fish: Xiphophorus maculatus — species aquarium dimensions, water, feeding and behaviour.
• OATA: platies and swordtails — group care, feeding, maintenance and social planning.
• RSPCA aquarium environment guidance — biological filtration and waste processing.