Poecilia velifera red leopard sailfin molly

Decide whether this hard-water livebearer fits

The red leopard sailfin molly (Poecilia velifera) is a poeciliid livebearer from the Yucatán–Quintana Roo and lower Usumacinta–Laguna de Términos systems in Mexico. It reaches 15 cm and suits a spacious, mature aquarium with basic, mineral-rich water. Seriously Fish says this species must be kept in moderately hard or harder water with a basic pH, so it suits a keeper prepared to test and maintain water rigorously, not an aquarium that runs soft or acidic.

FishBase records the species in freshwater and brackish environments, with adults feeding on worms, crustaceans, insects and plant matter. It also lists the wild species as Vulnerable. The red leopard wording identifies the aquarium colour form; care still has to be planned around the needs and adult size of Poecilia velifera.

Use the decisive numbers first

• Adult size: plan for 15 cm.
• Aquarium: use about 104 litres or more, with a base of at least 91 × 38 cm.
• Routine water: the FishBase, Seriously Fish and OATA overlap is 25–28°C, pH 8.0 and 15–18 dGH.
• Social plan: OATA’s molly guidance recommends at least three.
• Temperament: generally peaceful, but avoid timid fish and choose companions that tolerate hard water.

The Seriously Fish species profile gives a base of 91 × 38 cm and about 104 litres, while also advising as much space as possible. A small or crowded aquarium may impair development of the male’s large dorsal fin. The same profile describes this species as more difficult to maintain than others in its genus and says water quality must be maintained rigorously.

Understand the animal you receive

This fish is sold individually at a 6–7 cm dispatch size. That measurement describes the size sent, not the adult limit: plan the aquarium for 15 cm from the beginning. Dispatch size must not be used to infer sex or life stage, and one purchase supplies one fish.

Sex is guaranteed only when the selected option explicitly states male or female. This Poecilia velifera red leopard sailfin molly listing has no sex-guaranteed option.

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.

Choose it for the aquarium, not just the colour

The red-orange pattern, and the tall sail-like dorsal fin that males develop, can make this molly visually prominent, but colour does not change the space, water or social decisions. If you are comparing focal animals, browse the centrepiece fish collection, then check each candidate against your measured water and the behaviour of fish already in the aquarium.

A suitable home has three foundations in place before this animal is considered: enough floor space for a 15 cm fish, stable hard and basic water, and a stocking plan that allows molly companionship without crowding. The aquarium should include planted cover and open swimming room rather than filling every part of the tank with decoration.

Check the offer against your plan

1. Count one fish for each purchase quantity.
2. Build the social plan around at least three of this species, while recognising that the sexes in this offer are not guaranteed.
3. Allow for a 15 cm adult even though the fish is dispatched at 6–7 cm.
4. Confirm the FishBase, Seriously Fish and OATA overlap of 25–28°C, pH 8.0 and 15–18 dGH.
5. Check that the aquarium is mature, filtered and large enough before adding the fish.

Do not use the apparent sex, size or colour of the representative gallery animal as a promise about the individual supplied. Base the decision on the stated purchase unit and the husbandry requirements instead.

Plan the aquarium around the adult size

Allow for an adult length of 15 cm and use an aquarium of at least about 104 litres with a 91 × 38 cm base. The length and base matter together: volume supports water stability, while the footprint provides swimming room and space for cover without eliminating open water.

FishBase records 15 cm total length. Seriously Fish gives 15 cm standard length and recommends the 91 × 38 cm base with a volume of about 104 litres.

Separate dispatch size from long-term space

The 6–7 cm dispatch measurement is an arrival size. It is not a smaller adult form and must not be used to justify a reduced permanent aquarium. Starting with the adult plan also avoids having to move a growing fish after it has settled into a social group.

A simple space check is to work in this order:

1. Start with the base: provide at least 91 × 38 cm.
2. Check volume: aim for at least about 104 litres.
3. Add the group: allow extra room as stocking rises above a small group.
4. Preserve open water: plants and cover should not fill the whole swimming area.
5. Review every resident: total stocking must remain sensible rather than treating 104 litres as room for unlimited companions.

Use more space where the group is busy

Seriously Fish advises keeping the aquarium as large as possible because cramped or overcrowded conditions may impair development of the male’s dorsal fin. Extra volume also gives more capacity to absorb changes in waste production, but it does not replace filtration, testing or water changes.

Watch how the fish actually uses the aquarium. If one individual is persistently displaced from cover or feeding space, review the group and overall stocking rather than adding more decoration until no open water remains. The objective is a layout in which fish can move freely, feed without constant competition and withdraw behind plants when needed.

Keep the water hard, basic and stable

Keep this molly at 25–28°C, pH 8.0 and 15–18 dGH for routine aquarium care. This is the practical overlap of the Poecilia velifera ranges from FishBase and Seriously Fish with OATA’s group guidance for guppies and mollies.

FishBase records 25–28°C, pH 8.0 and 13–19 dGH for the species’ environment. Seriously Fish gives aquarium ranges of 22–28°C, pH 7.0–8.5 and 15–35 dGH. OATA gives 20–28°C, pH 7.0–8.0 and 8–18 dGH for guppies and mollies, narrowing the shared routine target to 25–28°C, pH 8.0 and 15–18 dGH.

Test before choosing the fish

Measure the aquarium rather than relying on the general reputation of local tap water. Use the water chemistry guide to identify the relevant tests, then compare your readings with the target through the water matcher. Check temperature, pH and general hardness together; a correct temperature does not compensate for soft or acidic water.

Prioritise minerals, not salt

Seriously Fish identifies calcium and magnesium hardness as crucial to long-term health and says salt is not necessary. Do not treat added salt as a substitute for suitable general hardness. This species can inhabit fresh or brackish conditions, but a freshwater aquarium still needs hard, basic water.

Keep replacement water close to the established aquarium conditions. Stability matters because repeated swings move the fish in and out of its suitable range even if an occasional isolated test appears acceptable.

Build a filtered aquarium with cover and swimming room

Use a mature biological filter in every aquarium housing this fish. The RSPCA’s aquarium welfare guidance explains that fish release toxic ammonia and that a working biological filter supports bacteria which convert ammonia to nitrite and then to the safer nitrate.

For an aquarium of about 104 litres, Seriously Fish recommends turnover of four to five times the aquarium volume each hour, corresponding to a filter rated at about 415–520 litres per hour. Treat that as a practical equipment range for the stated tank, then check that the completed layout still allows circulation without removing every calm or sheltered area.

Prepare the aquarium before livestock

Mature the filter before adding fish. Our first tropical aquarium guide explains the preparation sequence. OATA advises confirming that ammonia and nitrite are both zero before fish are introduced and increasing stocking slowly so the bacterial population can adjust to greater waste and feeding.

Balance plants with open water

Create a heavily planted layout with some floating cover and areas of open water. Gravel or sand can be used as the substrate. If live plants are not used, OATA suggests artificial plants and suitable ornaments to provide shelter; choose ornaments and artificial plants that will not injure long fins.

At 104 litres, Seriously Fish suggests roughly 100–150 W of heating to hold 22–28°C when the room is around 20°C. Select equipment for the actual aquarium and room, then verify the FishBase, Seriously Fish and OATA overlap target of 25–28°C with a thermometer rather than relying only on the heater setting.

Plan a small social group without crowding

Keep at least three of this sailfin molly together rather than mixing in other molly species. OATA’s molly guidance recommends companionship in a group of at least three and suggests two females for each male to reduce stress on females and other residents. Larger groups require more aquarium volume rather than simply fitting more fish into the minimum footprint.

This offer does not provide a guaranteed sex, so do not assume that ordering a particular quantity will produce the suggested ratio. Start with enough room for the planned group, observe interactions and avoid building a stocking plan that depends on receiving a particular sex.

Use behaviour to review the plan

• Normal access: each fish can reach food, open water and shelter.
• Persistent pursuit: review the group composition and space if one fish cannot withdraw.
• Repeated hiding: check for crowding, unsuitable companions and water-quality changes.
• Displacement at feeding: distribute suitable food so all group members have an opportunity to feed without increasing the total portion excessively.

Seriously Fish notes that males can be vigorous in pursuing mates. It also warns that overcrowding can affect dorsal-fin development. Space, cover and group composition therefore work together: adding plants may help break lines of sight, but it cannot correct an aquarium that is too small or overstocked.

Add livestock gradually

OATA advises increasing fish numbers slowly because beneficial filter bacteria need to respond whenever more livestock and feeding are added. A sudden rise in waste can produce new tank syndrome, with harmful ammonia or nitrite. Test after a stocking change and do not add another group while the aquarium is failing to hold both compounds at zero.

When considering a larger group, calculate the effect on every resident rather than looking only at molly numbers. The 104-litre figure is a starting minimum for this species, not a fixed allowance that overrides the needs of tank mates or the filter’s biological capacity.

Feed an omnivorous diet with animal and plant foods

Use a varied omnivorous diet that includes both animal foods and vegetable matter. FishBase records adults feeding on worms, crustaceans, insects and plant matter, while Seriously Fish describes wild feeding on zoobenthos and detritus and says most live, frozen and dried foods are accepted.

Build the staple around the recorded diet

Offer a quality dried food alongside an algae-based food, with vegetable items such as blanched spinach, cucumber or vegetable flake. Add small live or frozen foods such as daphnia, small bloodworm or tubifex for variety. Match every item to the fish’s mouth and remove uneaten vegetable pieces before they decay.

OATA recommends feeding guppies and mollies only what they can consume within a few minutes, once a day. That portion rule is more useful than a fixed pinch because fish size, group size and food density vary.

Adjust the portion by observation

• If food remains after a few minutes, reduce the next portion.
• If one fish consistently misses food, spread the same total amount across the feeding area.
• If interest in food falls, test water quality and look for other changes in behaviour or appearance.
• If body condition rises or falls, review the amount and balance rather than responding with an abrupt large feed.

Overfeeding leaves organic waste that breaks down in the aquarium and increases the load on the filter. A varied menu still has to fit within the once-daily, few-minutes portion. Variety means rotating suitable foods, not stacking several full portions into one feeding.

Maintain water quality every week

Change about 25% of the water at least once every week and test ammonia and nitrite at least weekly. OATA recommends zero milligrams per litre for both compounds and advises keeping nitrate no more than 20 mg/l above the normal tap-water level.

Use a repeatable weekly routine

1. Test ammonia, nitrite and nitrate before deciding that the aquarium is stable.
2. Siphon solid waste from the substrate while removing about 25% of the water.
3. Treat replacement tap water with conditioner to remove chlorine or chloramine.
4. Return water that is compatible with the established temperature, pH and hardness.
5. Check the filter for restricted flow or blockages.
6. Record unusual results so trends are visible before fish show severe changes.

Do not clean biological filter media under the tap. OATA advises rinsing it lightly in aquarium water removed during the partial change, reducing the loss of beneficial bacteria. Filter cleaning should preserve biological function rather than making every surface look new.

Respond to the result, not the calendar alone

A larger aquarium can be more stable, but volume does not make weekly care optional. The combination of a 15 cm adult size, a social group and daily feeding means waste production must be anticipated. Keep the biological filter mature, avoid sudden stocking increases and use test results to guide action.

After any increase in livestock or feeding, pay particular attention to ammonia and nitrite. The bacterial population needs time to adjust to the higher load, so stable readings should come before another stocking change.

Introduce the fish carefully and check the first month

Film every delivery continuously from before the parcel is opened. Show the parcel still sealed with the outer box visible, then open it in one continuous take and show the fish still inside the sealed bag. Arrange for someone to receive the parcel because live fish must not be left unattended. Open and inspect the parcel the same day it arrives, and if anything has gone wrong contact us that day with your order number and the unboxing video. Follow the current delivery and Live Arrival Guarantee policy: float the bag for 20–30 minutes before releasing the fish, and never pour the bag water into the aquarium.

The policy describes fish being hand-bagged in pure oxygen and placed in an insulated box, with a heat pack used when the weather calls for it. Read the current policy before delivery so the recipient knows the arrival and claim steps.

Complete the aquarium checks first

Before the fish is introduced, OATA advises checking that the aquarium is an appropriate size and that ammonia and nitrite are zero. Separately, confirm the FishBase, Seriously Fish and OATA overlap of 25–28°C, pH 8.0 and 15–18 dGH. Acclimatisation cannot correct unsuitable aquarium chemistry or an immature filter.

Use clear first-week checkpoints

• At release: float the bag for 20–30 minutes and keep bag water out of the aquarium.
• At each daily feed: check whether the fish approaches food and can feed without persistent displacement.
• During observation: look for changes in swimming, breathing, colour, fins, scales and hiding.
• At the weekly check: test ammonia and nitrite and complete the planned partial water change.

Review the first month as a pattern

Compare behaviour across several observations rather than treating one resting position as the whole picture. Repeated surface hanging, bottom sitting, erratic swimming, faster or slower gill movement, reduced feeding or a change in colour deserves a water test and a review of compatibility.

Keep stocking stable while the fish settles and while test results show how the filter is handling the load. Additions made too quickly can outpace beneficial bacteria. Four consistent weekly maintenance cycles provide a clearer view of water stability than one satisfactory reading on arrival day.

Act on health and behaviour changes early

Learn the fish’s usual swimming, feeding, colour and social behaviour so a change is easy to recognise. OATA highlights surface hanging, sitting on the bottom, erratic swimming, altered aggression or hiding, changed gill movement, white spots, fluffy growths, damaged fins or scales, body-condition changes and reduced feeding as signs that deserve attention.

Start with measurable conditions

Test ammonia, nitrite, nitrate, temperature, pH and hardness when behaviour or appearance changes. Ammonia and nitrite should remain at zero; use the FishBase, Seriously Fish and OATA overlap of 25–28°C, pH 8.0 and 15–18 dGH for the routine water target. Check filter flow, recent stocking changes, feeding and maintenance at the same time.

Do not respond to every symptom by adding salt. Seriously Fish identifies hard-water minerals as essential and says salt is unnecessary, so the first chemistry decision is to confirm suitable pH and general hardness.

Keep notes on when the change began, the measured water values and any recent additions or maintenance. Concrete observations make it easier to separate a chemistry, stocking or compatibility problem from a one-off movement. Continue routine care while seeking guidance unless an immediate water-quality result requires action.

Choose peaceful tank mates that tolerate hard water

Choose companions that are peaceful and comfortable with the FishBase, Seriously Fish and OATA overlap of 25–28°C, pH 8.0 and 15–18 dGH. Seriously Fish describes Poecilia velifera as a peaceful community fish but says it should only be kept with species that tolerate hard water.

Named possibilities include swordtails, platies, some gouramis, hardy corydoras or loricariids, and some barbs or tetras. These are conditional categories, not universal approvals: the exact species still has to match the water, aquarium size, adult stocking level and temperament.

Apply the screening rule in order

1. Water: reject a candidate that needs soft or acidic conditions.
2. Temperament: avoid timid fish because OATA advises that sailfin mollies should not be kept with them.
3. Space: calculate around adult sizes and the molly group, not dispatch measurements.
4. Behaviour: confirm that the particular gourami, barb, tetra, corydoras or loricariid is an appropriate community fish.
5. Feeding: make sure each resident can obtain its food without persistent displacement.

A brackish setup can include compatible chromides or gobies according to Seriously Fish, but the complete aquarium must be planned as a brackish community. Do not move a freshwater community into brackish conditions merely to add this molly.

For a species not named here, use the water–temperament–space screen and accept that compatibility depends on the exact combination. Ask us for one stocking and compatibility assessment if you want the whole proposed community checked together.

Manage social pressure and crossbreeding risks

Do not house this fish with other molly species, because Seriously Fish advises they may crossbreed. Seriously Fish specifically advises against other mollies because they may crossbreed. Swordtails and platies are named as alternatives within a hard-water community, subject to enough space and compatible behaviour.

Plan a group of at least three of this species. When sexes are known, OATA suggests two females for each male, and Seriously Fish also recommends this ratio because males may pursue females vigorously. The sex supplied through this offer is not selectable, so observation and spare capacity are more reliable than assuming a planned ratio will arrive.

Distinguish peaceful from passive

Generally peaceful does not mean socially inactive. Chasing can occur around mating behaviour, and a timid tank mate may spend too much time withdrawing. Plants and floating cover can create separation, while open water lets fish move without being trapped between decorations.

• If one fish is repeatedly chased, review sex balance where known, group size, cover and aquarium space.
• If a timid companion hides persistently, move away from that pairing rather than adding more fish.
• If long fins become damaged, inspect ornaments and review the behaviour of every resident.
• If feeding becomes competitive, spread the normal portion while ensuring it is consumed within a few minutes.

Plan for livebearing behaviour

This is a livebearer, and mixed-sex groups may produce young. Seriously Fish reports that aquarium forms can prey on their offspring and that heavily planted cover can improve fry survival. Do not use the possibility of young as a reason to exceed the aquarium’s stocking capacity.

Any increase in fish numbers increases feeding and waste, so the filter’s bacterial population and aquarium volume must be considered before young are retained. Monitor ammonia and nitrite and keep both at zero. A larger social group needs more space than the stated starting minimum, even when the individual fish are still small.

Answer common buyer questions

How big does the Poecilia velifera red leopard sailfin molly grow?

It reaches 15 cm. Plan the aquarium around that adult size rather than the 6–7 cm dispatch measurement.

What size aquarium does the Poecilia velifera red leopard sailfin molly need?

Use at least about 104 litres with a base of 91 × 38 cm. Seriously Fish gives these figures for the species and advises as much space as possible; OATA notes that more fish need a larger volume.

How many Poecilia velifera red leopard sailfin mollies should I keep?

OATA’s molly guidance recommends at least three. When the sexes are known, it suggests two females for each male; larger groups need more aquarium volume.

Is the Poecilia velifera red leopard sailfin molly suitable for beginners?

It can suit a careful keeper with a mature, spacious hard-water aquarium, but it needs rigorous water quality and is more difficult to maintain than others in its genus. Keep ammonia and nitrite at zero.

What does the Poecilia velifera red leopard sailfin molly eat?

Feed a varied omnivorous diet of quality dried and algae-based foods, vegetable matter and small live or frozen foods. Offer only what the group consumes within a few minutes once daily.

What temperature and pH does it need?

Keep the Poecilia velifera red leopard sailfin molly at 25–28°C, pH 8.0 and 15–18 dGH. These routine values are the overlap of FishBase, Seriously Fish and OATA’s molly guidance.

Is this fish aggressive or likely to nip fins?

Treat it as a generally peaceful community fish, while watching for persistent chasing when males pursue females. Avoid timid fish and provide planted cover plus open swimming room.

Which fish can the red leopard sailfin molly live with?

Consider swordtails, platies, some gouramis, hardy corydoras or loricariids, and some barbs or tetras only when the exact species tolerates the same hard water. Avoid other molly species, because they may crossbreed.

How does it arrive alive in the UK?

Film every delivery continuously from before the parcel is opened; show it still sealed, open it in one continuous take and show the fish still inside the bag. Someone must receive the parcel, and it must be opened and inspected the same day. Float the bag for 20–30 minutes before releasing the fish, and never pour bag water into the aquarium.

Check the care and policy references

• FishBase — Poecilia velifera: identity, family, native distribution, environment, recorded diet, maximum length and conservation status.
• Seriously Fish — Poecilia velifera: species aquarium dimensions, water ranges, layout, filtration, diet, behaviour and reproduction.
• OATA — How to look after guppies and mollies: group guidance on water quality, companionship, feeding, maintenance and health observations.
• RSPCA — Aquarium environment: general biological-filtration and fish-waste guidance.
• Tropical Fish Co delivery and Live Arrival Guarantee policy: packing, receipt, acclimatisation and claim steps.