Mosaic Elephant Ear Guppy (Poecilia reticulata) — Female

Female Mosaic Elephant Ear Guppy at a glance

The Mosaic Elephant Ear Guppy is a domestic strain of the guppy, Poecilia reticulata, and each purchase supplies one female fish at about 3–4 cm. She belongs in a mature, filtered aquarium at least 60 cm long with hard, neutral-to-alkaline water, living with other guppies and calm companions that leave fins alone. Before ordering, decide what you would do with fry: a female guppy can give birth long after her last contact with a male.

“Mosaic” and “Elephant Ear” are hobby trade labels for a selected colour pattern and fin appearance. Like Moscow, Cobra or Tuxedo, they describe how a line has been bred to look. They do not make a separate species, and they do not change what the fish needs: water, space, food and company are the same as for any guppy.

Is she the right fish for your aquarium?

• A good fit if you keep, or are setting up, a cycled community aquarium of 60 cm or longer with hard tap water, and you want a calmer group than a display of males alone.
• A useful addition to an existing guppy group that has too few females for its males.
• Think again if your water is soft and acidic, if the tank holds fin-nippers such as tiger barbs, or if you have nowhere to put fry.
• Wait if the aquarium is new and still shows ammonia or nitrite on test.

Why choose a female?

In the wild type, male guppies are the more colourful sex with the longer fins, and Seriously Fish notes that selective breeding has taken both to extremes. Females are larger and plumper, and although they are generally duller, aquarium-bred varieties can show intense colour in the tail fin. A few females give a group body and calm, and buying one changes the questions to answer before she arrives.

• Joining an all-female group: there is no new mating in your aquarium, but she may still carry sperm from before sale.
• Joining a mixed group: OATA suggests two females to each male, and Seriously Fish advises several, because males pursue females constantly.
• Living alone: not suitable. Guppies need companions of their own kind.

Sex is guaranteed only when the exact product or selected option explicitly states male or female. This Poecilia ret. female mosaic elephant ears listing is sold as female. Each purchase is one fish, so order the number you need for the group you are planning.

Where guppies come from

Wild guppies are native to Venezuela, Barbados, Trinidad, northern Brazil and the Guianas. FishBase’s species summary describes them in warm springs, weedy ditches and canals, very small streams and densely vegetated lakes, usually where predation pressure is low, and in habitats ranging from turbid lowland ponds to clear mountain streams. The species is listed as Least Concern by the IUCN and is one of the most popular aquarium fishes, with many standardised varieties. Aquarium strains such as this one are far removed from their wild ancestors in colour and finnage, but they share the same basic biology.

Pattern, colour and photographs

Every fish in a selected strain is a little different in pattern, colour intensity and fin shape. Gallery images have been digitally enhanced to improve image quality. Natural colour, pattern, size and maturity can vary between live animals. A female supplied at 3–4 cm may not yet have reached her full adult size or colour.

For the species in more depth, including its naming history and the reasoning behind our house recommendations, read our complete guppy care guide.

Aquarium size, filtration and heating

Guppies are small, but a group needs swimming length, steady water and room for any fry a female produces. Four references give slightly different starting points:

We follow the most cautious of these, the 60 cm length, because length gives a group room to swim and gives a female space away from persistent males. Litres alone cannot show whether a tank is suitable: the footprint, the filter, existing fish, the sex mix and any fry all change the answer.

Reading the label on a tank

• 20–25 litres: usually shorter than 60 cm, so not a permanent home for a guppy group.
• 45–50 litres: meets OATA’s litre floor, but still check length, filtration, water tests and the social plan.
• Around 60 litres: a common choice if the tank is at least 60 cm long; five guppies can be a sensible starting group rather than a maximum.
• 90 litres or more: more water adds stability and choice, but it does not remove the need to plan for fry.

Measure the internal dimensions to confirm the real water volume, and resist turning that number into a fish-per-litre rule. Watch the group itself: if one fish is chased, misses food or hides constantly, the tank needs a change of plan rather than another fish.

Cycle the filter before she arrives

The RSPCA’s aquarium environment advice is clear that no fish should be kept without a well set up and maintained filter. Fish release ammonia, which is toxic; a working biological filter grows beneficial bacteria that turn ammonia into nitrite, also toxic, and then into nitrate, which is safer. OATA adds that ammonia and nitrite should both read zero before any fish goes in, and that numbers should rise slowly, because the bacteria need time to catch up each time stock and feeding increase. Stocking too many fish too quickly causes ‘new tank syndrome’, when ammonia and nitrite climb high enough to make fish ill or kill them.

If this is your first aquarium, our step-by-step guide to setting up and maturing a first tropical tank covers the whole process before any livestock is ordered. Confirm that the tank is cycled with repeated water tests rather than by counting weeks.

Filter flow and heating

Seriously Fish suggests a filter that turns the water over four to five times an hour: for a tank of about 41 litres that is a filter rated around 165–205 litres per hour, with roughly 50 W of heating to hold its temperature range in a room at about 20°C. Larger tanks scale up accordingly. Guppies do best without strong currents, so choose and position the filter so that the flow never pins, tires or buffets the fish, and make sure the intake cannot endanger small fish or fry.

In most UK homes a guppy tank needs a thermostatic heater. Check the water itself with a separate aquarium thermometer rather than trusting the heater dial or the room temperature, and look at it daily when you feed.

Water values for a hard-water livebearer

Seriously Fish describes Poecilia reticulata as a hard-water fish: it may manage in soft or acidic water, but long-term keeping should be in moderately hard or harder water. Different references publish different ranges because they measure different things, from wild records to practical aquarium advice.

We recommend 22–28°C, pH 7–8 and a general hardness of 8–18 dGH. The pH and hardness figures come from OATA’s combined guppy and molly sheet, which is broad guidance for a group of livebearers, and they sit comfortably inside the wider Seriously Fish ranges. The FishBase figures describe where the species has been recorded in the wild, and the cooler ends of the FishBase and Seriously Fish ranges fall outside our routine range; they are not targets for a home aquarium.

Why tap water needs testing

UK tap water is not one chemistry. Supplies differ from region to region and can be blended or changed by the water company, so read a recent report for your area and test the water you actually use. Treat every top-up and water change with a conditioner that removes chlorine and chloramine, and make changes gradually so temperature and hardness do not swing.

A worked example

Suppose your tap water tests at pH 7.6 with a general hardness of 12 dGH, and the aquarium holds 25°C. All three readings sit inside the values we recommend, so the job is to keep them steady with matched water changes. If the same test showed pH 6.4 and 3 dGH, your supply is softer and more acidic than a guppy needs for long-term keeping, and a community built around soft-water fish would suit it better than guppies.

Guppies also occur in brackish water, and FishBase notes a wide salinity range. That is not a reason to add aquarium salt. Leave salt and mineral products out unless you have a measured reason and have checked that every fish and plant in the tank will tolerate them.

Tools that help

Our guide to which aquarium water values to test and why explains ammonia, nitrite, nitrate, pH and hardness in plain terms. Once you have readings, the water parameter matcher compares your aquarium with a fish’s stated range, which is a quick way to see whether your tap water suits a hard-water fish such as this one before you order.

Plants, cover and swimming space

A guppy aquarium works best with open water for swimming and feeding, and planted areas for cover. Seriously Fish calls the species unfussy, but notes that a planted tank with floating vegetation is appreciated and that strong currents should be avoided. OATA recommends gravel or sand, live plants for cover and, where live plants are not used, artificial plants and ornaments that give shelter without injuring long fins.

• Floating plants give newborn fry cover near the surface and improve their chances.
• Planted zones let a female move out of a pursuing male’s line of sight.
• Open water keeps room for the group to swim and feed together.
• A secure cover belongs on every guppy aquarium.

More decoration is not automatically better. A 2025 guppy study found that physical enrichment improved several behavioural and stress-hormone measures, but high enrichment also brought more biting. Add structure, watch how the group uses it and rearrange if one fish is still cornered or kept from food.

Dense cover also raises fry survival. That can be welcome in a deliberately managed breeding set-up, but it means more young fish needing space, filtration and homes, so plants are not a substitute for a population plan. Keep the front of the aquarium clear enough to count the group and see each fish at feeding time.

Feeding a female guppy

Guppies are omnivores. In the wild they feed on zooplankton, small insects and detritus, according to FishBase, and Seriously Fish describes wild fish as mainly insectivorous. Aquarium-bred strains are far removed from their ancestors and accept most foods, so the aim is a balanced routine rather than a special diet.

A practical routine

• Staple: a good-quality flake or granule with a high algae content, sized for small mouths.
• Variety: small live or frozen foods such as daphnia, small bloodworm or tubifex, bought from biosecure aquarium sources.
• Amount: OATA advises feeding only what the fish can eat within a few minutes, once a day.
• Clean-up: remove anything left uneaten before it breaks down and releases waste into the water.

Watch the whole group at feeding time and make sure a newcomer or a shyer fish is not being crowded out, rather than assuming the group’s appetite covers her.

Body shape and condition

A healthy female is naturally deeper-bodied than a male, and her belly looks fuller after a meal or as she matures. A rounded abdomen is not a reliable sign of pregnancy on its own, so keep portions steady rather than feeding more because she looks heavy. A thin, pinched belly or a female that stops eating is the more urgent signal.

If fry appear and you decide to raise them, they need food small enough for their mouths and especially careful water testing, because extra food in a small nursery quickly affects water quality.

Arrival day and her first fortnight

Prepare and test the aquarium before dispatch so she goes straight into stable, cycled water. Fish are hand-bagged in pure oxygen and packed in an insulated poly box, with a heat pack when the weather calls for it, and we email the tracking number and your confirmed delivery date so you know when to be in. Our delivery and Live Arrival Guarantee page sets out coverage, packing and claim terms in full.

On the day

1. Arrange for someone to be at the delivery address to receive the parcel; live fish cannot be left unattended.
2. Start one continuous unboxing video before anything is disturbed: show the sealed parcel with the outer box visible, open it in the same take and show the fish still inside the sealed bag. The Live Arrival Guarantee needs this video, and the parcel must be opened and inspected on the day it arrives.
3. Float the sealed bag in the aquarium for 20–30 minutes to acclimatise her slowly.
4. Release her into the aquarium and never pour the bag water into your tank.
5. If anything has gone wrong, message us the same day, WhatsApp is fastest, with your order number and the unboxing video, and we will arrange a replacement or refund.

Adding her to an established group

OATA advises increasing fish numbers slowly, because the filter bacteria must grow each time stock and feeding rise. One female is a small addition, but if you are building a group, add fish in stages and test between additions. Watch how any males react: constant pursuit of the newcomer means the group needs more females, more cover or a different plan.

The first two weeks

Watch quietly rather than handling or rearranging. OATA describes a healthy fish as having clear, bright eyes, undamaged fins, intact scales, no ulcers or bumps and normal swimming. Test ammonia and nitrite over the first days, as the filter adjusts to one more fish and a little more food.

If breathing, balance or swimming worries you, test the water straight away and follow the reporting steps promptly. Continuing distress should not be written off as travel stress.

Weekly care, health checks and quarantine

A weekly routine

• A partial water change of 25% at least once every week, using a siphon to lift waste from the gravel.
• Water tests at least once a week, so ammonia and nitrite never build up.
• Tap-water conditioner in all replacement water to remove chlorine or chloramine.
• A check of the filter for blockages. When the media needs cleaning, rinse it lightly in tank water removed during the water change, never under the tap, so the beneficial bacteria survive.

That routine follows the OATA guppy and molly care sheet, which stresses that good husbandry is essential because guppies and mollies can be stressed by even small amounts of ammonia.

Signs to watch for

• Swimming: hanging at the surface, sitting on the bottom or erratic swimming.
• Colour: turning darker or paler than normal.
• Temperament: more aggression or more hiding than usual.
• Breathing: gill covers moving faster or slower than normal.
• Appearance: white spots, fluffy growths, lost scales or damaged fins.
• Condition and appetite: weight change, reduced feeding or no interest in food.

These are warning signs rather than a diagnosis. Test ammonia, nitrite, nitrate, pH and temperature first, then look at the filter, heater, recent maintenance, food, any new arrivals and how the group is behaving. Record what you see with dates or photographs. The RSPCA’s fish health and welfare advice covers normal and worrying signs, and OATA’s directory of UK fish vets helps you find a professional diagnosis. Avoid choosing salt, heat or medication from one symptom; in the UK, use lawfully labelled products and follow veterinary direction.

Quarantine new fish

Seriously Fish warns that many mass-produced guppies are less hardy because of inbreeding and over-production, and more prone to disease. That is a good reason to quarantine any new fish, including this one, before she joins an established community. The MSD Veterinary Manual recommends at least 30 days in a separate system with its own equipment, biologically supported filtration and regular testing, and longer where problems are suspected.

Fry, stored sperm and population planning

Guppies are livebearers, so a female gives birth to live young rather than laying eggs. FishBase records that females mature at about three months of age and males at about two, so a young mixed group can start breeding quickly. Seriously Fish calls breeding very easy, which is exactly why it needs planning.

Stored sperm

A female guppy can keep viable sperm after mating and use it for later broods. Seriously Fish reports females producing young for six months or more with no male present, and peer-reviewed research documents storage over several months. Even in an all-female tank, she may give birth later if she met a male before sale.

What a pregnant female can look like

Keepers often watch for a gravid spot, a darkened area just behind the anal fin, together with a fuller outline. Treat these as hints rather than certainties: a rounded abdomen or dark patch is not a reliable sign of pregnancy on its own, and colour varies between domestic strains. Seriously Fish gives broods of roughly 5 to 100 young after a gestation of about four to six weeks, but timing and numbers vary between females and conditions.

Avoid confining a female in a small, uncycled container to give birth; it is not a safe shortcut. If you move fry, move them to water that already matches the main aquarium.

Never release aquarium fish

Guppies have been introduced far beyond their native range, often for mosquito control. FishBase records rare to non-existing effects on mosquitoes and negative to perhaps neutral effects on native fishes. Never release guppies, fry, plants, snails or aquarium water into a pond, drain, stream or any natural water. Rehome surplus fish responsibly and dispose of old water and substrate where nothing can reach a watercourse.

Tank mates and group make-up

Seriously Fish describes the guppy as a very peaceful fish that does well in a quiet community aquarium with other livebearers, rasboras, corydoras, small loricariids and tetras. Treat that list as a set of candidates: each companion still has to share hard, neutral-to-alkaline water, leave long fins alone and fit the aquarium once both groups are counted.

Six checks before adding a companion

1. The water ranges match comfortably, not just at the edges of each fish’s range.
2. Neither animal can swallow or injure the other as adults.
3. There is no fin-nipping, territorial or food-competition risk.
4. The usable footprint still suits both social groups.
5. Every animal can reach food and refuge.
6. You have a separation option ready if behaviour changes.

Fish to avoid

Fin-nippers are the clearest mismatch. Seriously Fish names tiger barbs and serpae tetras, and OATA advises against keeping guppies with any species that might nip their fins, such as barbs. Large or predatory fish that could swallow or injure a guppy are also unsuitable.

Combinations that need caution

• Bettas: not a sensible default. Display, territorial and long-fin interactions vary between individuals, and even a larger planted aquarium cannot make the pairing safe for certain.
• Shrimp and small invertebrates: small shrimp and young may be eaten, so check each species rather than assuming all adult invertebrates are safe.
• Endler’s livebearers: a separate species that can interbreed with guppies, covered below.

Male, female or mixed group?

Peer-reviewed research shows that male harassment can change where females spend their time. Give her space and planted refuges, check that she feeds and keeps condition, and keep a cycled separation tank available. Repeated chasing, cornering, hiding or fin damage needs action, not another fish.

If you are building a larger group, the guppy collection shows other strains and sexes; check each listing for its exact sex and sale unit before settling your ratio.

Guppies and Endler’s livebearers

Endler’s livebearer, Poecilia wingei, was formally described as a separate species in 2005 and is listed as valid in Eschmeyer’s Catalog of Fishes. Laboratory research confirms that guppies and Endler’s livebearers can hybridise through first- and second-generation crosses. Keep the two in separate aquariums if you want either line to stay true, and never pass on hybrid offspring as either pure species.

Mosaic Elephant Ear Guppy questions

How big does a Mosaic Elephant Ear Guppy get?

Female guppies are the larger sex. Seriously Fish records a standard length of up to 60 mm, measured without the tail, and FishBase gives 5 cm for males, so plan for an adult female of about 5 to 6 cm plus her tail fin.

What size aquarium does a guppy need?

Use a mature, filtered aquarium at least 60 cm long for one small group. That is our house plan, based on the 60 cm minimum in FishBase's aquarium note. OATA's guppy and molly guidance gives at least 45 litres for a small group of the smaller livebearers, and Seriously Fish suggests a base of 45 × 30 cm, so treat those figures as floors rather than targets.

How many guppies should I keep with a female Mosaic Elephant Ear Guppy?

Keep her in a group. OATA advises at least three guppies, with two females to each male in a mixed group, and FishBase's aquarium note gives groups of five or more, which is the starting group we recommend. That can be all female, or mixed with several females to each male if you are ready for fry.

Is a Mosaic Elephant Ear Guppy suitable for beginners?

Yes, for a prepared beginner. Guppies are peaceful and undemanding once the aquarium is cycled, but they are not suited to a new tank that still shows ammonia or nitrite. Decide the sex mix of the group and what you will do with fry before you buy.

What do guppies eat?

Guppies are omnivores. OATA recommends a good-quality flake or granule with a high algae content, plus small live or frozen foods such as daphnia or small bloodworm, fed once a day in an amount the fish can eat within a few minutes.

What temperature and pH does a Mosaic Elephant Ear Guppy need?

We keep guppies at 22–28°C. OATA's guppy and molly guidance gives pH 7.0–8.0 and a general hardness of 8–18 dGH, with zero ammonia and nitrite. Seriously Fish describes the species as a hard-water fish, so avoid soft, acidic water for long-term keeping.

Is the Mosaic Elephant Ear Guppy aggressive, and does it nip fins?

No. Seriously Fish describes the guppy as a very peaceful fish, and guppies are far more likely to have their own fins nipped than to nip others. Males do chase females persistently, so give a female planted refuges and enough companions to share that attention.

Which tank mates can live with a Mosaic Elephant Ear Guppy?

Seriously Fish lists other livebearers, rasboras, corydoras, small loricariids and tetras for a quiet community aquarium, as long as each species shares hard, neutral-to-alkaline water and leaves fins alone. Avoid fin-nippers such as tiger barbs and serpae tetras, and remember that small shrimp and newborn fry may be eaten.

How does a Mosaic Elephant Ear Guppy arrive alive in the UK?

She is hand-bagged in pure oxygen and packed in an insulated poly box, with a heat pack when the weather calls for it, then carried by a licensed live-animal courier with tracking. Someone must be at home to receive the parcel. Film one continuous unboxing video from the sealed parcel to the fish still in the sealed bag, then float the bag for 20–30 minutes before release; the Live Arrival Guarantee needs that video.

Sources and further reading

These public sources support the care, identity and welfare guidance on this page.

• FishBase: Poecilia reticulata species summary: family, native range, wild habitat and diet, recorded length, maturity and aquarium notes.
• Seriously Fish: Poecilia reticulata species profile: aquarium size, water ranges, diet, behaviour, sexing and reproduction.
• OATA: how to look after guppies and mollies: UK trade-body water guidance, maintenance routine, feeding and compatibility.
• RSPCA: choosing an aquarium, and fish health and welfare: filtration, cycling and signs of illness.
• MSD Veterinary Manual: management of aquarium fish: quarantine and water-quality-led diagnosis.
• OATA: find a fish vet: a UK directory for professional diagnosis and treatment.
• Eschmeyer’s Catalog of Fishes: Poecilia reticulata: accepted name, authorship (Peters, 1859) and type locality.
• Poeser, Kempkes and Isbrücker (2005): the formal description of Poecilia wingei, with its valid status confirmed in Eschmeyer’s Catalog of Fishes.
• Tropical Fish Co: guppy care guide and delivery and Live Arrival Guarantee policy, both linked above.