Neon Endler Guppy (Poecilia endler)

Choose this small social livebearer for a planned aquarium

The Neon Endler Guppy (Poecilia endler) is a small freshwater livebearer in the Poeciliidae family. Its native range lies in Venezuela’s Campoma and Buena Vista lagoon systems, and FishBase records a maximum length of 2 cm standard length. Standard length stops at the base of the tail. This active, social fish suits a prepared beginner who can provide mature filtration, stable medium-hard water, swimming space and a deliberate population plan.

FishBase now lists it as Poecilia wingei. Eschmeyer’s Catalog of Fishes also treats Poecilia wingei as the valid name in Poeciliidae. Research comparing guppy relatives supports its identity as a distinct species while showing why colour and body measurements alone cannot establish pedigree. This matters when preserving a documented line, because Endlers and common guppies can hybridise.

Our easy care assessment means the fish can suit a beginner who starts with the right aquarium; it does not mean a bowl, uncycled tank or improvised mixed-sex group is suitable. Use a mature aquarium of about 41 litres or more with at least 60 cm of usable length under our conservative house screen. Plan for five or more fish where filtration, other occupants and the sex plan allow.

Small adult size reduces neither the need for space nor the consequences of unstable water. The useful question is whether every fish can swim, feed and move out of another fish’s path while the filter keeps ammonia and nitrite at zero.

Understand the animal supplied and plan for adult size

One purchase supplies one live fish at a dispatch size of 1–2 cm. That measurement describes the fish sent, not a separate life-stage or sex promise. Plan its permanent aquarium around the recorded adult figure, its social needs and the total population rather than treating a small arrival as permission to begin in temporary housing.

Sex is guaranteed only when the selected option explicitly states male or female. This Neon Endler Guppy 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.

Use 2 cm standard length as the adult figure

FishBase records 2 cm standard length as the maximum used throughout this page. Other references apply different measurements: Seriously Fish gives 2.5 cm standard length, while the original species description reports a largest female of 30.4 mm standard length in a separate stream sample. These figures describe measured fish, not a promise that every individual will reach the same length.

Standard length excludes the tail, so the visible nose-to-tail measurement can be longer. Aquarium planning must also allow for continuous swimming, courtship, group movement and possible fry. A tank can therefore be too restrictive even when its inhabitants occupy little physical volume.

Choose identity and population together

The word “Neon” describes this trade form’s appearance; it does not establish a locality line or ancestry. A morphological and molecular comparison supports Poecilia wingei as distinct but also reports overlapping appearance among related guppies. Avoid keeping common guppies with Endlers because the two species will crossbreed.

Decide before adding the fish whether the aquarium will hold a correctly sexed single-sex group or a mixed group. Mixed sexes can reproduce readily, while single-sex groups still require monitoring for pursuit, territorial behaviour and feeding access. You can compare Endler guppy forms and documented sex-labelled offers when planning a group, without assuming that colour alone identifies sex or ancestry.

Build the aquarium around length and filter capacity

Use a mature aquarium of about 41 litres or more and apply our conservative screen of at least 60 cm in length for an adult group. Seriously Fish gives a 45 × 30 cm base and about 41 litres for this species; Tropical Fish Co adds the longer 60 cm screen so active swimming, courtship and routes around other fish remain part of the decision. Choose an aquarium that satisfies the space, water and population requirements together.

Start with five or more where capacity and the sex plan allow. Five is our house recommendation, while OATA’s guppy guidance gives at least three. Neither number is a maximum, and neither turns litres into a fixed allowance per fish. Count all existing animals, their adult sizes, their own group needs and any likely fry before deciding whether the aquarium has room.

Create open routes and useful cover

• Keep an open horizontal route for continuous swimming.
• Add live plants and floating plants for cover and line-of-sight breaks.
• Arrange cover so a pursued fish can move away without becoming trapped.
• Use smooth ornaments that will not catch fins.
• Protect the filter intake where a small fish or fry could be drawn against it.
• Fit a secure lid to reduce escape risk.

A planted layout is strongly recommended, but plants do not replace filtration or water testing. Dense planting can also help fry survive, so match the amount of cover to the population plan. If additional young fish would exceed capacity, more cover is not a substitute for separating sexes or arranging responsible rehoming.

Size filtration to the complete aquarium

Seriously Fish uses a turnover of four to five times the aquarium volume per hour. Its worked example for about 41 litres is a filter rated around 165–205 litres per hour. Treat that as a starting calculation: media capacity, obstruction, maintenance condition and the needs of every occupant still affect performance.

Prepare biological filtration before livestock enters the aquarium. The first tropical aquarium guide explains how to mature the system and confirm that it processes waste. Add fish gradually because feeding and livestock increase the amount of ammonia the bacterial community must handle.

Keep water inside the shared husbandry range

Keep the aquarium at 24–28°C, pH 7.0–8.0 and 15–18 dGH. These values are the overlap between Seriously Fish’s species-level range of 24–30°C, pH 7.0–8.5 and 15–35 dGH and OATA’s group guidance of 20–28°C, pH 7.0–8.0 and 8–18 dGH. The narrower overlap gives a practical routine target without extending beyond either range.

Test the source water and aquarium rather than judging hardness from a postcode or assuming all tap water is alike. Read the actual pH and general hardness, then compare the result with the stated range. Our water chemistry guide explains what the measurements mean, and the water matcher helps compare measured aquarium values with this plan.

Prioritise stability over rapid adjustment

• Use a thermostatically controlled aquarium heater where room conditions cannot hold 24–28°C.
• Check the actual water temperature with an independent thermometer.
• Make chemistry changes gradually and measure the result.
• Treat replacement tap water with conditioner before it enters the aquarium.
• Avoid unmeasured pH corrections or fixed tap-and-RO recipes.

Temperature, pH and hardness are not interchangeable. A tank at the right temperature can still be too soft, while a suitable hardness reading does not show whether ammonia is present. Record each value separately so a change can be traced instead of hidden inside a general impression that the water looks clear.

Keep nitrogen waste under control

Maintain ammonia and nitrite at zero. OATA advises keeping nitrate no more than 20 mg per litre above the normal tap-water level. Test the tap supply as well as the aquarium when interpreting nitrate, because a reading cannot be judged without knowing the starting level.

When a result moves outside the normal pattern, check the measurement, temperature, filter operation, recent feeding, livestock additions and maintenance history. Correct the cause with measured changes; repeatedly chasing one number can create the rapid swings this fish should avoid.

Maintain the biological system each week

Change about 25% of the water at least once a week, using conditioned replacement water that is close to the aquarium’s temperature. Siphon accumulated solid waste from accessible areas while leaving enough established surfaces and filter media undisturbed to preserve biological stability.

The RSPCA explains why a working biological filter is essential: fish release toxic ammonia, bacteria convert it to nitrite, and further bacteria convert nitrite to safer nitrate. Clear water can still contain ammonia or nitrite, so testing must guide the routine.

Use this weekly check

Clean filter media only when flow or accumulated waste requires it. Rinse it lightly in aquarium water removed during the water change, never under the tap, because chlorine or chloramine may damage the established bacteria. Avoid replacing all mature media together.

Respond to change before adding more fish

Pause population growth when tests become unstable, filter flow falls, fish miss food or pursuit increases. Adding another animal to solve social tension can increase waste and crowding before it improves group structure. Restore water quality and usable space first, then reassess the whole group.

During the first month after a livestock change, keep a written record of test results and behaviour. A simple sequence of date, temperature, ammonia, nitrite, nitrate, feeding response and unusual behaviour makes patterns visible. It also distinguishes a one-off observation from a developing problem.

Stable care is a connected system: suitable water reduces physiological stress, the filter processes waste, water changes export nitrate and dissolved pollutants, and observation shows whether every fish can use the environment. Skipping one part makes the remaining measurements harder to interpret.

Feed small complete portions that match its omnivorous diet

Use an appropriately small complete flake or granule as the staple. Seriously Fish describes the species as an omnivore that feeds on zoobenthos and detritus in the wild and should receive some vegetation in its aquarium diet. OATA recommends a good-quality flake or granule with algal content, supplemented with suitably small live or frozen foods.

Offer one daily portion that the group can finish within a few minutes. This schedule comes from OATA’s guppy and molly guidance. Particle size matters for a fish reaching only 2 cm standard length: choose pieces the smallest individual can take without repeatedly spitting them out.

Build variety around a complete staple

• Use a small complete flake or granule with appropriate plant content as the nutritional base.
• Add small live or frozen items such as daphnia, small bloodworm or tubifex where suitable.
• Choose cyclops or comparably small items when larger frozen food cannot be handled.
• Spread food across more than one point so a pursued or slower fish can feed.
• Remove food that repeatedly remains after the feeding period.

Watch the whole group rather than the quickest fish. A vigorous individual finishing its portion does not show that every fish has eaten. Check whether smaller, slower or pursued animals approach food, swallow it and retain a reasonable body condition.

Adjust from observations, not guesswork

If food remains, reduce the next portion and remove the decaying excess. If one fish repeatedly misses food, distribute smaller particles over a wider area and inspect social pressure. A sudden loss of appetite calls for water and health checks rather than richer feeding.

Visible algae is not a complete diet. It can contribute grazing opportunities, but its presence does not show that the aquarium provides all required nutrients. Store dry food as directed, avoid repeated thawing and refreezing of frozen food, and keep feeding tools clean.

Fry require food they can physically take and a mature system able to process the extra feeding. When young fish appear, reassess filter capacity, water tests and total population immediately. Do not move them into an uncycled container or use uncontrolled adult predation as the population plan.

Plan the social group before mixing sexes

Keep a planned group of five or more where aquarium capacity and the sex plan allow. This is Tropical Fish Co’s conservative house recommendation. OATA advises at least three guppies and suggests two females per male to reduce pressure on females, while Seriously Fish notes that females may act territorially and several can help disperse bullying.

No ratio removes the need to watch individuals. Males are described as peaceful towards one another, but courtship and display competition can still produce prolonged pursuit or feeding exclusion. Females can also compete. Space, sight breaks and a mature separation option remain necessary for every group structure.

Use mature anatomy when assessing sex

In mature fish, a male has a narrow modified anal fin called a gonopodium, while a female has a broader triangular anal fin. Males are often smaller and more colourful, but colour, body size or a rounded abdomen alone is not a reliable basis for a sex decision. The dispatch measurement must not be used to infer maturity.

Expect mixed groups to reproduce

Poecilia wingei is a livebearer and mixed-sex groups can reproduce readily. Decide before forming the group where young fish could live in a mature system and how they could be responsibly rehomed. More births increase both biological load and competition for swimming and feeding space.

A life-history study followed ten litters and 122 fry under one laboratory regime. Use it as confirmation that reproduction can be prolific, not as a countdown or brood-size promise for an individual fish. Condition, age, ancestry and husbandry vary.

If fry appear unexpectedly, test the water, review filter capacity and provide appropriately small complete food. Separate sexes only when identification is confident and mature housing is ready. Early population decisions are safer than waiting until crowding, ammonia or persistent pursuit forces an emergency move.

Follow the arrival sequence and act on health changes

Prepare the mature aquarium before the journey. OATA advises checking that ammonia and nitrite are zero before adding fish. Our delivery and Live Arrival Guarantee policy explains the current packing, receipt and reporting process. Fish are hand-bagged in pure oxygen, placed in an insulated poly box and given a heat pack when weather calls for it. Someone must be present to receive the live animal.

Use the store arrival procedure

1. If practical, start filming before the parcel is opened, showing the parcel still sealed and the outer box visible.
2. Open the parcel in one continuous take and show the fish still inside the sealed bag.
3. Float the bag in the aquarium for 20–30 minutes before releasing the fish.
4. Release the fish without pouring the bag water into the aquarium.

After release, assess swimming, balance, breathing and fin position. Compare behaviour over time rather than judging colour alone, because pale or darker colour can accompany several different conditions. The useful question is whether the fish begins to move and breathe normally in suitable tested water.

Use water-quality checks first

Warning signs include surface gasping, sitting on the bottom, loss of balance, erratic swimming, persistent hiding, clamped or damaged fins, spots, fluffy growths, wounds, unusual swelling and reduced feeding. RSPCA fish-health guidance supports checking water and equipment promptly when behaviour or appearance changes.

• Test ammonia, nitrite, nitrate, pH and temperature.
• Inspect the heater, filter flow and intake.
• Review recent livestock additions, feeding and maintenance.
• Record changes with clear photographs and times.
• Seek veterinary help when signs are severe, persistent or worsening.

Do not choose salt, heat or medication from one symptom. Similar signs can have different causes, while unsuitable treatment can add stress or affect filtration. Isolate a fish only in a separate mature system with suitable water and equipment.

Treat an unusual spinal curve as an individual health concern rather than diagnosing its cause by appearance. A study of one captive line found spinal deformities in 22 of 600 fish and discussed genetic, nutritional, environmental and traumatic contributors. That result describes one line under documented conditions, so assessment should focus on the affected fish’s welfare and circumstances.

Screen every companion for predation, fins and water needs

Choose only small, peaceful companions that share the Seriously Fish and OATA overlap of 24–28°C, pH 7.0–8.0 and 15–18 dGH and leave enough room for every species’ adult size and social group. Compatibility remains conditional because individuals, aquarium dimensions, sex balance, feeding speed and layout all affect the result.

Avoid any species large enough to eat an Endler. OATA also advises against species that may nip guppy fins, giving barbs as an example. Do not rely on a juvenile companion’s present size; assess the size and feeding behaviour it develops as an adult.

Use named examples as candidates, not promises

Seriously Fish names dwarf corydoras, small rainbowfish such as Iratherina werneri or Pseudomugil species, and peaceful tetras as possible companions. Each candidate must still pass the water, space and behaviour checks for the exact species being considered.

Check each proposed community companion for water, adult size and temperament. Seriously Fish considers this species unsuitable for a general community because its small size increases predation risk. A carefully screened community of suitably small peaceful fish is a narrower plan than adding it to any peaceful-looking collection.

Feeding compatibility matters as much as aggression. A fast surface-feeding companion can exclude a small Endler without attacking it. Watch whether every fish reaches appropriately sized food and whether the group can move away from competitors.

When breeding or preserving identity is the goal, a species aquarium is the clearest plan. Seriously Fish recommends keeping it alone when breeding is attempted. Common guppies should be excluded because fertile hybridisation can occur.

Treat shrimp safety and peaceful behaviour as conditional

No fish is guaranteed shrimp-safe. Adult Neocaridina or Amano shrimp may coexist where water, minerals, space and feeding all suit both animals, but small shrimp and young can be eaten. Dense cover reduces exposure without ensuring survival, and shrimp must not be treated as a replacement for cleaning or water changes.

Watch actions rather than labels

The useful signs of compatibility are normal swimming, regular feeding, intact fins and the ability of every animal to use shelter or open water without being persistently displaced. A “peaceful” label cannot account for courtship, female territoriality, competition around food or one unusually assertive individual.

Observe at more than one time of day and include feeding periods. Brief display is different from prolonged pursuit that prevents rest or food access. Record which fish initiates the behaviour, where it happens and whether layout changes alter the pattern.

Keep a mature separation option ready before combining uncertain companions. An uncycled emergency container exchanges one welfare problem for another. The backup space must have suitable temperature, filtration and water chemistry.

Protect documented identity

Avoid common guppies because they can produce fertile hybrids with Poecilia wingei, and appearance cannot reliably determine ancestry. Record parentage and describe offspring honestly whenever identity matters.

The complete Endler Guppy Care Guide brings the population, identity, water and compatibility decisions together. Use its screening approach for the exact aquarium rather than assuming one successful combination will behave identically in another tank.

Answer common Neon Endler Guppy questions

How big does the Neon Endler Guppy get?

FishBase records a maximum of 2 cm standard length. Plan around this adult figure while remembering that standard length stops at the base of the tail.

What size aquarium does a Neon Endler Guppy need?

Seriously Fish gives a 45 × 30 cm base and about 41 litres, while Tropical Fish Co applies a conservative screen of at least 60 cm length for an adult group with mature filtration.

How many Neon Endler Guppies should I keep together?

Plan five or more where aquarium capacity and the sex plan allow. Tropical Fish Co recommends five or more, while OATA’s guppy guidance gives a floor of at least three.

Is the Neon Endler Guppy suitable for beginners?

It can suit a prepared beginner and has an easy store care assessment, but it still needs a mature filtered aquarium, tested water, a social plan and capacity for possible fry.

What does the Neon Endler Guppy eat?

It is omnivorous. Feed an appropriately small complete flake or granule with plant content as the staple, add suitably small live or frozen variety, and offer one daily portion eaten within a few minutes.

What temperature and pH does a Neon Endler Guppy need?

Keep it at 24–28°C, pH 7.0–8.0 and 15–18 dGH; these values are the overlap of Seriously Fish guidance for the species and OATA guidance for guppies and mollies.

Is it aggressive or likely to nip fins?

Seriously Fish describes males as peaceful towards one another but says females may act territorially. Monitor pursuit and fin condition, and avoid companions that may nip guppy fins, such as barbs.

Which animals can this fish live with?

Seriously Fish names dwarf corydoras, small rainbowfish such as Iratherina werneri or Pseudomugil species, and peaceful tetras as candidates where water and space overlap. Avoid predators and common guppies because Endlers and common guppies will crossbreed; small shrimp may be eaten.

How does this fish arrive alive in the UK?

It is hand-bagged in pure oxygen, packed in an insulated poly box with a heat pack when weather calls for it, and carried by a licensed live-animal courier. Someone must receive it. If practical, start filming before opening the sealed parcel, show the fish still in the bag, float the bag for 20–30 minutes, then release the fish without pouring bag water into the aquarium. We strongly recommend an unboxing video when practical: it helps us investigate arrival concerns faster, resolve them with less back-and-forth and understand packing or transit issues so we can reduce recurrence. Video is optional and clear photos are accepted. Never delay necessary animal care to record evidence.

Consult the scientific and welfare references

• FishBase: Poecilia wingei — accepted identity, family, Venezuelan distribution and maximum recorded length.
• Seriously Fish: Poecilia wingei — aquarium dimensions, water ranges, diet, behaviour and named companion candidates.
• OATA: Guppies and mollies — UK group guidance on water, feeding, maintenance, social care and compatibility.
• Tropical Fish Co delivery and Live Arrival Guarantee policy — packing, receipt, acclimatisation and reporting procedure.
• RSPCA aquarium environment guidance — biological filtration and waste processing.
• RSPCA pet fish health guidance — warning signs and water-quality-first checks.
• Eschmeyer’s Catalog of Fishes — scientific identity and family placement.
• Original description of Poecilia wingei — type locality, measured material and diagnostic description.
• Comparison of guppy relatives — distinction of P. wingei and overlap in visible morphology.
• Spinal deformities in one captive line — case observations and possible contributing factors.
• Life-history traits of Endler’s fish — observations from ten litters under one laboratory regime.