Pineapple Swordtail (Xiphophorus hellerii)

Decide whether this swordtail fits your aquarium

The Pineapple Swordtail (Xiphophorus hellerii) is an ornamental colour form of a freshwater poeciliid from North and Central America. FishBase places the natural range from the Rio Nantla in Veracruz, Mexico, to north-western Honduras and records a maximum length of 14 cm. This active livebearer suits a prepared beginner or experienced keeper who can provide a mature filter, firm water chemistry, a social group and a long swimming footprint.

Plan around an aquarium of about 108 litres with a base of at least 120 × 30 cm. Seriously Fish says this should be the smallest aquarium considered. FishBase gives an 80 cm minimum aquarium length, so the longer 120 cm base provides the stronger planning standard for adult movement and social management.

Keep at least three swordtails together. OATA’s group guidance recommends at least three and advises two females for each male when the sexes are known. A larger aquarium is needed as the group, other residents or future offspring increase the biological and social load.

Keep the aquarium at 22–27°C, pH 7.0–8.0 and 10–12 dGH. These routine values lie within the ranges from FishBase and Seriously Fish while also fitting OATA’s narrower swordtail guidance. Maintain ammonia and nitrite at 0 mg/l and keep nitrate no more than 20 mg/l above the normal level in the tap water.

OATA describes platies and swordtails as generally undemanding and easy to keep, so we rate this fish as easy when those space, water and social requirements are met. The rating does not reduce the need to prepare the adult aquarium before adding the fish.

Understand the fish and size you select

One purchase supplies one Pineapple Swordtail. Use the live size selector to choose the labelled 4–5 cm or 6–8 cm size, then set the quantity to the number of individual fish required. The size you select is the size supplied, not the adult size. Both labels describe dispatch size, so plan the aquarium around the recorded 14 cm adult length from the beginning.

Sex is guaranteed only when the selected option explicitly states male or female. This Pineapple Swordtail listing has no sex-guaranteed option. Build the group around the fish’s observed behaviour and adult characteristics instead of treating body size, colour or a tail extension in the gallery as a promise about the animal selected.

Seriously Fish explains that adult males tend to be smaller than females and possess a gonopodium together with the characteristic extension of the lower caudal-fin lobe. Some ornamental forms can develop other extended fins, including in females, so fin shape must be considered alongside the anal fin when mature fish are assessed.

The gallery images are representative of this type of animal rather than photographs of the exact animal supplied, so colours can look slightly different from the live animal. The visible fish has a golden-orange body, dark-edged scales, translucent fins and a long black-edged lower tail extension among plants, wood and gravel. Use that scene to recognise the broad Pineapple appearance, while allowing for individual differences in colour, markings and fin development.

Check the purchase plan

• Count one animal for each unit placed in the basket.
• Choose the dispatch-size label separately from the quantity.
• Prepare for a 14 cm adult even when selecting the smaller size.
• Plan a group of at least three, while recognising that each purchase adds one fish.
• Allow room to revise the group if adult male rivalry develops.

The Pineapple name identifies the ornamental form rather than a separate wild species or collection locality. FishBase uses Green swordtail as the species common name, while the scientifically correct spelling is Xiphophorus hellerii with two final letters “i”.

Plan the aquarium around the adult size

Use an aquarium with a base of at least 120 × 30 cm and a volume of about 108 litres. Seriously Fish presents those dimensions as the smallest that should be considered for Xiphophorus hellerii. Base dimensions matter because an aquarium can have adequate volume but still be too short or narrow for sustained swimming and social separation.

Plan for an adult length of 14 cm. FishBase records 14 cm total length for male or unsexed fish, while Seriously Fish gives 140 mm standard length. Use the single 14 cm planning figure throughout the stocking calculation and give the fish clear horizontal swimming room rather than arranging the aquarium around its smaller dispatch measurement.

Use the footprint before the litre figure

Aquascaping must preserve the usable footprint. Seriously Fish recommends a heavily planted arrangement and notes that floating plants, driftwood roots or branches can diffuse the light and create a more natural feel. Keep plants and wood around the margins where they can provide cover, while retaining broad lanes through which a 14 cm fish can turn and swim.

FishBase records adults mainly in rapidly flowing streams and rivers with heavy vegetation, as well as warm springs, weedy canals and ponds. That varied habitat supports a layout combining plant cover with open movement rather than either a bare box or a completely blocked thicket.

Work through one example

A 120 × 30 cm aquarium of about 108 litres meets the species-level starting dimensions. Three swordtails then satisfy OATA’s minimum social number, but the calculation is not finished if other fish already occupy the same water. Compare every resident at adult size, account for décor that reduces swimming room and leave capacity for the filter to process the combined waste. Increase the aquarium size when the adult community no longer fits that footprint comfortably.

Prepare and mature the adult aquarium before introducing livestock. Our first tropical aquarium guide explains the setup sequence, while the species measurements above decide whether that aquarium is physically suitable for this swordtail.

Keep water inside the overlapping ranges

Keep Pineapple Swordtails at 22–27°C, pH 7.0–8.0 and 10–12 dGH. This routine range is an overlap: FishBase records 22–28°C, pH 7.0–8.0 and 9–19 dH; Seriously Fish gives 16–28°C, pH 7.0–8.0 and 10–25 dGH; OATA gives 22–27°C, pH 7.0–8.0 and 4–12 dH for the swordtail group. Using the shared range keeps each routine value inside every named reference.

Test the aquarium rather than judging hardness from a regional reputation or pH from appearance. The water chemistry guide explains temperature, pH, general hardness, carbonate hardness and nitrogen-cycle readings. Enter measured values in the water matcher to compare the aquarium with this fish’s care range.

Control waste before adjusting chemistry

Maintain ammonia at 0 mg/l and nitrite at 0 mg/l. OATA recommends keeping nitrate no more than 20 mg/l above its normal level in the tap water. Test at least weekly and repeat a test whenever fish show changes in breathing, swimming, feeding, colour or social behaviour.

The RSPCA explains that a working biological filter supports bacteria that convert toxic ammonia to nitrite and then to the safer nitrate. A clear aquarium can still contain dissolved ammonia or nitrite, so visual clarity never replaces testing.

OATA strongly recommends changing 25% of the water at least once each week. Treat replacement tap water with conditioner to remove chlorine or chloramine before it enters the aquarium. Keep replacement water close to the aquarium’s temperature and make measured, controlled adjustments rather than producing repeated swings in pH or hardness.

Record readings in the same units each time. A simple weekly log makes a trend visible before fish behaviour changes and shows whether feeding, additions or filter maintenance have altered the biological load.

Combine plant cover, swimming room and filtration

Run a well-established filter continuously and provide a degree of water movement without turning the aquarium into an exhausting current. Seriously Fish says filtration need not be particularly strong, although this species appears to appreciate some movement. In an aquarium of about 108 litres, it suggests turnover of four to five times the volume each hour, corresponding to a filter rated around 430–540 litres per hour.

Filter ratings are a starting point rather than a substitute for observation. Media, pipework and accumulated debris can reduce practical flow. Position the outlet so water circulates through the aquarium while leaving sheltered planted areas where fish can leave the main current.

Arrange the aquarium in zones

A dark substrate and heavy planting suit the presentation described by Seriously Fish, but décor must not remove the required swimming footprint. Secure wood and other structures so routine maintenance cannot dislodge them. Check behind equipment and around dense planting during daily counts because a pressured fish may remain out of normal view.

Protect the biological filter

Check the filter for blockages during weekly maintenance. OATA advises rinsing dirty filter media lightly in aquarium water removed during a partial water change, never under the tap, because chlorine or chloramine can harm the established bacterial population. Preserve mature biological media whenever mechanical dirt is removed.

Add fish gradually. OATA warns that adding livestock too quickly can leave the bacterial population unable to process the increased waste and feeding load, producing new tank syndrome. A larger group should therefore be planned as a sequence of measured additions, with ammonia and nitrite checked as the biological demand changes.

Watch the entire group after maintenance. Rapid breathing, surface gathering or an abrupt change in swimming calls for immediate checks of temperature, ammonia, nitrite and filter flow. Correct the environmental cause before assuming that a fish simply needs more food.

Feed a balanced omnivore diet once a day

Use a good-quality dried omnivore food as the staple, with ingredients that cover both animal and plant material. Seriously Fish reports that wild stomach contents include aquatic and terrestrial invertebrates, organic detritus, algae and other plant matter. FishBase likewise records worms, crustaceans, insects and plant matter, so a varied omnivore diet fits the species better than relying on one treat.

Offer small live, frozen or freeze-dried foods such as Daphnia, Artemia and chironomid larvae as part of that variety. OATA also names small bloodworm and tubifex for platies and swordtails. Match particle size to the fish so that each animal can take food cleanly without repeated spitting or uneaten fragments sinking into the aquarium.

Use a simple feeding decision

Feed once a day and offer only what the fish consume within a few minutes. This schedule comes from OATA’s platy and swordtail guidance. Watch each animal rather than measuring the portion only by how quickly the most dominant fish reaches the food.

Spread food across more than one point when a dominant swordtail intercepts the first portion. Confirm that smaller fish and quieter group members eat, then stop when the group has finished its measured allowance. Remove persistent leftovers because decaying food adds waste and can drive ammonia, nitrite or nitrate upwards.

Respond to what you see

• If food remains after a few minutes, reduce the next portion and remove the excess.
• If one fish misses every feeding, spread the same total portion across separate areas.
• If appetite falls across the group, test temperature, ammonia and nitrite before changing foods.
• If one fish loses condition despite eating, compare its intake, social access and other health signs.

Enthusiastic approaches at feeding time do not by themselves justify a larger portion. Use body condition, water tests and the amount actually consumed to judge the routine.

Manage a social group as adult traits develop

Keep at least three swordtails. OATA recommends companionship for both platies and swordtails and suggests two females for each male to reduce pressure on females and other inhabitants. Apply that ratio when adult sex is known, while providing enough space to revise the group if its eventual composition creates repeated chasing.

Male swordtails can be aggressive towards one another. FishBase states this directly, and Seriously Fish explains that males in confined spaces can form dominance hierarchies and spend substantial time maintaining their positions. More swimming length and plant cover provide additional room and shelter, but persistent pressure still requires a change to the group or accommodation.

Read behaviour by repetition

Adult males possess a gonopodium, a modified anal fin used in reproduction, and usually show the lower tail extension associated with the swordtail name. Females have a triangular anal fin, and OATA says only male swordtails have the characteristic sword. Seriously Fish adds an important qualification: ornamental strains can show other extended fins, including in females, so assess mature anatomy rather than one decorative fin alone.

These fish are livebearers and give birth to live young. Seriously Fish also notes that females can store viable sperm for months. A group can therefore produce fry after its composition changes, and surviving young add to the aquarium’s space, filtration and feeding demands.

Plan for population change

Check the adult capacity before retaining young or adding further swordtails. Plants and other cover may shelter fry, but every surviving fish eventually contributes to the biological load. Increase accommodation before crowding develops rather than relying on the original group calculation indefinitely.

Keep social decisions separate from colour selection. The Pineapple pattern does not determine temperament, sex or position within the hierarchy. Judge each fish by repeated behaviour, mature anatomy and its access to food and shelter.

Follow the arrival and acclimatisation procedure

Prepare the mature destination aquarium before the parcel arrives. Keep it at the FishBase, Seriously Fish and OATA overlap of 22–27°C, pH 7.0–8.0 and 10–12 dGH. OATA advises confirming ammonia and nitrite are both 0 mg/l, and the adult stocking calculation must still work after the new fish joins the group.

Tropical Fish Co hand-packs fish in pure oxygen inside an insulated poly box and adds a heat pack when the weather calls for it. A licensed live-animal carrier transports the parcel, with tracking sent for the journey.

Use the store’s arrival steps

1. Have someone present to receive the parcel because live fish cannot be left unattended.
2. Start a short continuous unboxing video while the parcel is still sealed. Film every delivery from the sealed parcel onward, showing it being opened in one continuous take and the fish still inside the bag before floating or releasing.
3. Float the bag for 20–30 minutes before releasing the fish.
4. Do not pour the bag water into the aquarium.

These steps come from the Tropical Fish Co delivery and Live Arrival policy. The same page sets out the packing, reception and claim requirements.

Limit the first addition to what the filter can process

OATA advises increasing fish numbers slowly because the beneficial bacteria in a mature filter must adjust whenever fish and feeding increase. Test ammonia and nitrite after an addition and pause further stocking if either becomes detectable.

Healthy fish should have bright, clear eyes, intact scales, undamaged fins and an appropriate swimming response. Compare the newcomer with its own behaviour over time rather than expecting it to match the representative gallery fish in colour or fin development.

Maintain the aquarium and act on health changes

Change 25% of the water at least once each week and test ammonia and nitrite at least weekly. OATA strongly recommends this routine for platies and swordtails. Use a siphon to remove settled waste, condition replacement tap water and keep the new water close to the aquarium’s established temperature and mineral values.

Check filter flow and inspect the media for blockages during maintenance. Rinse dirty media lightly in the aquarium water removed during the change. Preserve the established bacterial population by keeping tap water away from biological media and by avoiding unnecessary replacement of mature media.

Use a repeatable weekly check

• Record temperature, pH and general hardness.
• Confirm ammonia and nitrite remain at 0 mg/l.
• Compare nitrate with the tap-water baseline and keep the rise within 20 mg/l.
• Check filter flow before and after maintenance.
• Count the group and inspect eyes, fins, scales, body condition and swimming.
• Compare feeding response and social position with the previous week.

OATA highlights changes in swimming, colour, temperament, breathing, appearance, body condition and feeding as useful warning signs. Examples include hanging at the surface, sitting on the bottom, erratic swimming, unusual hiding, faster or slower gill movement, white spots, fluffy growths, damaged fins, altered weight or reduced interest in food.

Test water quality before choosing any health response because environmental and social problems can produce visible changes. Record the readings, recent additions, feeding and maintenance so the pattern is clear. Contact us for further guidance when changes continue or several fish are affected.

Use the first month as a baseline

Keep a brief log of water readings, appetite and interactions through the first month. This creates a practical baseline for the individual fish and helps separate normal variation from a genuine change. Continue the same weekly checks after the aquarium appears settled.

Screen tank mates by water, pace and adult behaviour

Pineapple Swordtails are generally peaceful and can live with other species, but compatibility is conditional. OATA cautions that larger swordtails can be boisterous and may chase more timid tank mates. FishBase and Seriously Fish also establish that males can be aggressive towards one another, especially where confined space concentrates a hierarchy.

Start with shared water requirements. A prospective companion must remain healthy at 22–27°C, pH 7.0–8.0 and 10–12 dGH. It must also fit the aquarium at adult size and have enough room after at least three swordtails and the existing residents are counted.

Apply four checks in order

Other peaceful fish may be suitable when they pass all four checks. Timid fish require particular caution because repeated chasing can cause them to hide or lose feeding access. A peaceful label alone is insufficient when one species is much more active or assertive than the other.

Other swordtails share the same species requirements, but that does not make every group combination straightforward. Additional males can intensify rivalry, while mixed sexes can lead to fry and a rising population. Increase the footprint and filtration capacity before expanding the group.

Browse the livebearers collection to compare other fish, then assess each candidate independently for adult size, water chemistry and behaviour. Collection membership is not a compatibility guarantee.

Compatibility remains individual and conditional even after the measurable checks pass. Have a practical way to separate fish if persistent chasing, injury or loss of feeding access develops. Contact us with the aquarium dimensions, measured water values and complete resident list for a stocking assessment.

Adjust the community when social pressure appears

Judge compatibility by repeated outcomes rather than a single display. A brief chase that ends with both fish returning to normal swimming differs from continuous pursuit that prevents one animal from feeding or leaving cover. Record which fish initiates the interaction, where it happens and whether the target can disengage.

Use the observed problem to choose the response

Plants, roots and branches provide cover, while open lanes preserve swimming room. Keep both functions in balance: a bare aquarium offers little shelter, but an overfilled layout removes swimming room from a fish that can reach 14 cm.

Male rivalry requires particular attention because it is recorded for the species, not merely inferred from general community behaviour. Confined groups may spend substantial time maintaining a hierarchy. More room can reduce forced contact, but a persistently targeted fish still needs a direct welfare response.

Large swordtails may also chase timid companions without showing the same male hierarchy. Check whether the target resumes ordinary swimming, feeds and retains intact fins. Continued hiding, appetite loss or injury means the pairing is failing in that aquarium.

For animals outside the peaceful-fish guidance, make the assessment from adult size, feeding biology, water overlap and likely interaction. Do not rely on a universal list. The decisive question is whether every resident can maintain normal behaviour, body condition and food access in the actual aquarium.

Answer common Pineapple Swordtail questions

How big does a Pineapple Swordtail get?

It reaches 14 cm. Plan the aquarium around that adult length rather than the 4–5 cm or 6–8 cm dispatch size.

What size aquarium does it need?

Use an aquarium of about 108 litres with a base of at least 120 × 30 cm; Seriously Fish says this should be the smallest considered.

How many Pineapple Swordtails should I keep together?

Keep at least three. OATA’s swordtail guidance recommends companionship and suggests two females for each male when adult sexes are known.

Is a Pineapple Swordtail suitable for beginners?

Yes, for a prepared beginner: OATA describes swordtails as generally undemanding and easy to keep, but they still need a mature filter, suitable water and adult swimming space.

What does this fish eat?

Feed a quality dried omnivore food once a day, with Daphnia, Artemia or bloodworm for variety and a plant or algal component reflecting its recorded diet.

What temperature, pH and hardness does it need?

Keep it at 22–27°C, pH 7.0–8.0 and 10–12 dGH; this is the overlap of FishBase and Seriously Fish species ranges with OATA’s swordtail guidance.

Is a Pineapple Swordtail aggressive or likely to nip fins?

Males can be aggressive towards one another, and OATA says larger swordtails may chase timid fish; provide space and plant cover and act on repeated chasing or fin damage.

Which kinds of animals can it live with?

It may live with other peaceful fish that share 22–27°C, pH 7.0–8.0 and 10–12 dGH and can cope with active swordtail behaviour; every pairing remains conditional.

How is a Pineapple Swordtail packed for arrival in the UK?

It is hand-packed in pure oxygen inside an insulated poly box, with a heat pack when weather calls for it, and travels with a licensed live-animal carrier. Someone must receive it and start a short continuous unboxing video for every delivery while the parcel is still sealed, then film it being opened and the fish still in the bag before floating the bag for 20–30 minutes, releasing the fish and keeping bag water out of the aquarium.

References used for identity and care

• FishBase: Xiphophorus hellerii — scientific identity, family, native range, recorded length, environment, diet and male behaviour.
• Seriously Fish: Xiphophorus hellerii — aquarium footprint, water ranges, filtration, décor, diet, hierarchy and adult sex traits.
• OATA: How to look after platies and swordtails — group numbers, routine water care, feeding, maintenance, health observations and broad compatibility.
• RSPCA aquarium environment guidance — biological filtration and the nitrogen cycle.