Gold Balloon Molly (Poecilia latipinna)

Meet the gold balloon molly

A gold balloon molly is a sailfin molly, Poecilia latipinna, from an aquarium line bred for a golden body and a stubby, rounded outline. Until now this page spelled it "ballon molly gold", which is also how a lot of people type it into a search box. Ballon, baloon and balloon all lead to the same fish.

Two things separate it from a wild molly. One is colour. The other is shape: a wild sailfin is a slim fish, while this form is short, arch-backed and round in the belly because its backbone has developed abnormally. That second point deserves a straight explanation, and you will find it in the next section, ahead of the care advice.

Quick reference

• Species: Poecilia latipinna, the sailfin molly, family Poeciliidae.
• Form: balloon, a short-spined, rounded line kept going by selective breeding.
• Largest wild fish on record: 15 cm total length (FishBase); balloon mollies are a small variety.
• Temperature: 20 to 28 °C.
• Chemistry: pH 7.0 to 8.5 in hard water.
• Smallest sensible aquarium: 80 litres.
• Company: three or more, with two females for every male.
• Food: algae and vegetable matter first, with modest amounts of live or frozen food.

One fish per quantity, sex unselected

There is only one option on this listing. Each quantity added to your basket is one gold balloon molly. Males and females are not picked for this listing, and no dispatch size is listed. Order three and you could receive any mix of sexes. Mollies live best with more females than males, so think about that now rather than once the fish are home. Group balance is covered further down.

With no size given, set the aquarium up for an adult fish. A balloon molly will not reach a wild sailfin's 15 cm, but it still needs space for a group and water that stays stable.

What "gold" means in mollies

Among fancy mollies, gold is a recognised colour type rather than a loose description. Wikipedia's fancy molly article, which draws on Tropical Fish Hobbyist magazine, describes gold mollies as yellow-gold like albino mollies, but with dark eyes and occasionally scales edged in red. That is the colour this listing is named after. There are no photos on this page, so take those as features of the gold type in general, not a portrait of the individual fish you will receive.

Sexing your fish

Check the anal fin, the small fin on the underside towards the tail. In males it develops into a gonopodium, the modified fin used to fertilise the female internally; in females it stays fan-shaped. Males also grow the tall, sail-like dorsal fin that gives the species its common name, and FishBase calls that fin its most distinctive characteristic. With a balloon fish, the gonopodium is the surer guide.

The welfare question: should you keep a balloon molly?

Before ordering, you should know exactly what the balloon shape is. Plenty of people assume a balloon molly is just a well-fed one. It is not, and good care will neither cause the shape nor cure it.

A short, malformed backbone

In 2019, Shao and co-authors published a study in the journal Genes on what they called the dwarf white sailfin molly, which they say is also known as the balloon belly molly. They examined the fish's skeletons with X-rays and bone staining. Dwarf and normal fish turned out to have the same vertebra count, 27 to 29, so the short body is not the result of missing bones. The vertebrae themselves are dysplastic, meaning they have grown abnormally. The result is a short spine and a convexly arched back, where the normal fish were slender and flat. The researchers also tied the trait to two regions of the genome and three candidate genes. The shape is written into the fish's genetics.

The cost to the fish

Wikipedia sums up balloon mollies as a small variety with an extremely deformed abdominal cavity. Seriously Fish is blunter. It says the balloon variety is, in its opinion, grotesque, with a body that is malformed and rounded. It warns that the condition can cause swim bladder and digestive problems and may bring about premature death. So a gold balloon molly is a sailfin molly with a compromised body, and its care has to allow for that every day.

Our honest advice

If what you want is the gold colour and the lively character of a molly, with a natural skeleton, look at the gold leopard sailfin molly mix. It is the same species, listed as sailfin mollies rather than a balloon form. If you have already decided on a balloon molly, commit to giving it the best conditions you can. That means a settled tank, hard water, light meals heavy on plant food, slow water movement and peaceful neighbours. The silver balloon molly is the same species and body shape in a different colour, so it needs exactly the same care and the two can be kept together.

From coastal ditches to the aquarium: the sailfin molly's background

All balloon mollies come from a wild North American fish. FishBase defines the native range as running from the Cape Fear drainage in North Carolina to Veracruz in Mexico. Wikipedia fills in the route: south to Florida, round the Gulf of Mexico through Texas, and on to the Yucatán Peninsula.

Where wild sailfins live

This is a fish of the coastal lowlands. FishBase lists still or slow, warm water in small creeks and drains, ponds, lakes, sloughs, and the quiet, often weedy backwaters and pools of streams. It also calls the species abundant in tidal ditches and brackish canals. Wikipedia adds estuaries, lagoons, river deltas, swamps and mangroves, and records that sailfin mollies can tolerate salinity as high as 87 parts per thousand. That number is a survival limit in the wild, and it is quoted here as such, not as advice for your aquarium. Seriously Fish describes the usual habitat as heavily vegetated coastal streams, ponds, swamps, canals and ditches. Calm water and plenty of plants come up again and again in those descriptions.

A grazer at heart

According to FishBase, the diet is mainly algae, topped up with rotifers, small crustaceans such as copepods and ostracods, and aquatic insects. Seriously Fish describes wild sailfin mollies as almost exclusively herbivorous. Wikipedia adds mosquito larvae to the list of invertebrates eaten. That plant-heavy diet is the starting point for feeding your gold balloon molly.

How fancy mollies came about

Aquarium mollies have a tangled family tree. Seriously Fish records that P. latipinna has been bred into many colour morphs and has also been crossed with other molly species, especially P. sphenops, the short-finned molly. Wikipedia's fancy molly article calls the origin of fancy mollies unclear and lists P. sphenops, P. gillii, P. latipinna and P. velifera as the parent species usually named. Its sailfin molly article notes that first-generation hybrids often show novel fin shapes. We sell this fish under the name Poecilia latipinna, which is how the Genes study above treats the balloon belly molly. We mention the wider picture because it explains why balloon mollies are not all built identically.

Sailfin molly or Yucatán molly?

You will see two sailfin species on molly labels, ours included: Poecilia latipinna, the sailfin molly, and Poecilia velifera, the Yucatán molly. Seriously Fish notes that the two look alike and that P. latipinna can be told apart by dark, rectangular spots in its dorsal fin. With colour-bred fish and a mixed fancy-molly ancestry in the background, the name on a listing is a trade identification rather than a lab result. The care on this page follows the sailfin molly sources throughout.

Wild status and the release problem

FishBase records an IUCN Red List assessment of Least Concern, dated February 2019. The bigger issue is where mollies turn up outside their range. FishBase lists introductions to many countries, several of them reporting harmful ecological effects. Seriously Fish says introduced mollies often outcompete native species, and Wikipedia names established populations in New Zealand, Hawaii, California and Iraq, among others. Whatever happens, never let an aquarium fish go into the wild. Ask a local aquatic shop or club to help if you need to rehome one.

Tank size and layout for a short-bodied fish

Size the aquarium for the species and the group, not for one small fish. OATA, the UK trade association for ornamental fish, puts the minimum for sailfin mollies at 80 litres. Seriously Fish suggests a base of 76 by 38 cm, about 87 litres. Since mollies should live in threes or more, those figures are a starting point. More water also dilutes waste and steadies temperature, both of which help a fish with little physical reserve.

How to lay it out

Seriously Fish recommends dense planting combined with open swimming space. For a balloon molly, place the open water where the fish can reach it easily. Keep the middle and front clear, put plants along the back and sides, and avoid narrow gaps between rocks and wood that a rounded fish would have to squeeze through. Seriously Fish also warns that this very vegetarian fish may destroy soft-leaved plants, so choose sturdier species or expect some damage.

Algae is not the enemy here. Seriously Fish recommends common green algae as a supplementary food for sailfin mollies. Scrape the viewing pane and let a few stones or the rear glass grow a green film for the fish to graze between meals.

Water movement

OATA says a filter is always essential, and the filter should be fully mature before any fish go in. What changes with a balloon molly is the flow. Seriously Fish connects the balloon body with swim bladder problems, so a fish of this shape should not have to hold its place against a strong current. Diffuse the outlet with a spray bar, aim it at the glass, or lower the pump setting until there are quiet zones at the surface and among the plants.

Warmth

Fit a heater with a thermostat and a thermometer you can see without moving anything. Keep the tank away from radiators, windows and doors where sun or draughts could swing the temperature. Wikipedia lists low water temperature among the triggers for swim bladder disorder, so heater faults matter more than usual for this fish. A daily glance at the thermometer at feeding time catches most problems early.

Before you order, have ready

• A tank of at least 80 litres, with its filter matured and its outflow softened.
• Heater, thermostat and a readable thermometer, holding a steady temperature.
• Plants around the edges and clear open water in the middle.
• Test results for ammonia, nitrite, nitrate, pH and hardness that meet the targets in the next section.

Water chemistry and a weekly routine

Sailfin mollies need hard, alkaline water, and almost every source says so in numbers. Here are the targets, with sources, followed by a routine that keeps them steady.

The targets

• Temperature: FishBase and OATA both give 20 to 28 °C. Seriously Fish gives a narrower 21 to 26 °C. Holding the tank between 21 and 26 °C satisfies all three sources.
• pH: Seriously Fish gives 7.0 to 8.5, and OATA's guppy and molly care sheet gives 7.0 to 8.0. Aim between 7.0 and 8.0.
• General hardness: Seriously Fish gives 15 to 35 °dGH for this species, and OATA gives 8 to 18 °dH for mollies in general. The two overlap at 15 to 18 °dH.
• Carbonate hardness: OATA gives 5 to 15 °dKH.
• Ammonia and nitrite: zero, according to OATA.
• Nitrate: OATA's limit is 20 mg per litre above whatever your tap water contains.

Reading your water company's figures

Test kits usually report hardness in degrees (°dH or °dGH), but water company reports often give it as milligrams per litre of calcium carbonate. To convert, divide the mg/l figure by about 17.8. The 15 to 18 °dH overlap above works out at roughly 270 to 320 mg/l as calcium carbonate. A kit reading in your own tank is still the number to trust, because filters, rocks and substrate can change it.

If your tap water tests soft, sort out how you will raise and hold the hardness before buying. Ask an aquatic shop for a method suited to your water. Mollies belong in hard water, and soft water is a poor match for them.

Salt: not needed

Because wild sailfins live in brackish canals and ditches, many keepers assume aquarium mollies need salt. Seriously Fish says otherwise: salt is not necessary. The minerals behind hard water, calcium and magnesium, are what it calls crucial to the species' long-term health. A well-mineralised freshwater tank is the right home for a gold balloon molly. A brackish tank is possible, but it is a different project and would rule out most freshwater companions.

A routine for every week

1. Test: OATA recommends testing at least once a week for ammonia, nitrite, nitrate, pH and hardness.
2. Record: jot the results in a notebook or on your phone. Slow trends show up on paper long before they show in the fish.
3. Change water: OATA strongly recommends a 25% partial change every week. Dechlorinate the new water and match its temperature.
4. Clean lightly: clear the viewing glass and remove any obvious waste, but leave a grazing film of algae elsewhere.
5. Check kit: make sure the heater light is cycling and the filter flow has not dropped.

Nothing here is complicated. Its value comes from doing it every week, which is what protects a fish that has swim bladder and digestive weak points.

What to feed a gold balloon molly, and how much

Two facts settle the feeding plan. Sailfin mollies are built to graze algae and plants, and Seriously Fish links the balloon body to digestive problems. That means plant food first and small amounts of it.

The menu

OATA suggests a good-quality flake or granule with a high algae content as the main food. It adds that mollies benefit from live or frozen foods such as daphnia and small bloodworm. Seriously Fish says tank-bred sailfin mollies will take varied foods but still need vegetable matter, such as blanched spinach or a vegetable-based flake. It also notes that males given too little greenstuff can develop poorer dorsal fins. Whatever the shape of your fish, the diet behind that advice is the right one.

Preparing greens

Blanching softens spinach so a molly can tear it. Dip a few washed leaves in boiling water for a moment, cool them in cold water, and squeeze out the excess. Offer a small piece clipped to the glass or weighted down, and take out whatever is left at the end of the feed so it does not foul the water. A vegetable flake does the same job with less fuss on busy days.

Portions

OATA's rule is to give only what the fish will eat within a few minutes, once a day. Hold to it. A balloon molly is round whatever you feed it, so its body is no guide to whether it has eaten enough. Watch the food instead. Anything still uneaten after a few minutes means you gave too much, so net it out and cut back next time.

Overfeeding also hits the water. Wikipedia's swim bladder disease article names overeating and constipation among the causes, and links constipation to the high nitrate that builds up from overfeeding. Light meals, a clean tank and fewer swim bladder problems all go together. For a fish whose body cavity is already compressed, keep meals small and leafy.

Making sure it gets its share

In a mixed aquarium, quicker fish can clear the surface before a round-bodied fish arrives. For the first week or two, stay and watch the whole of each feed. If your gold balloon molly is missing out, spread the food more widely, feed at both ends of the tank, or add a sinking vegetable tablet where it tends to feed.

Companions and group structure

Seriously Fish rates the sailfin molly as a sound choice for hard-water community tanks. It adds two warnings: mature fish may pick on much smaller fish, and males can be aggressive towards each other, particularly when spawning.

Males, females and how many

Both OATA and Seriously Fish advise two females for each male. OATA recommends keeping at least three mollies, adding more in the same ratio, to reduce stress on the females and on everything else in the tank. Wikipedia describes the males as the more aggressive sex. They show off to females by raising their enlarged dorsal and tail fins, and the females choose partners partly on those fins.

Wikipedia also notes that males suffer higher mortality than females from predators and disease. For your tank, the figure that matters is the ratio: a group of six works out at two males and four females, and nine fish at three males and six females.

Because this listing does not select sex, plan to adjust. A larger first order gives better odds of a workable balance. Over the first few weeks, watch who is chasing whom. If one female is getting no rest, you can add more females, find a new home for a male, or thicken the planting so she has somewhere to break the line of sight.

Good neighbours

Seriously Fish suggests other livebearers and some catfish as tank mates. Whatever you choose must also want hard, alkaline water. With that settled, look for:

• Peaceful livebearers of a similar size that share the same water.
• Other balloon mollies, such as the assorted balloon molly or the calico marble golden balloon molly, which have the same body shape and needs.
• Calm catfish suited to hard water for the lower levels.

Who to leave out

Leave out very small fish, which adult mollies may harass. Leave out fin-nippers and fast, rough species that would chase a rounded fish or reach every meal first. Leave out species that need soft, acidic water, because one of the two would always be compromised. A gold balloon molly already carries the risk of swim bladder trouble, and a stressful tank mate makes that harder.

Stocking pace

Add fish gradually and test the water after each addition. A crowded tank gives quarrelling males more reasons to fight and pushes nitrate up. Keeping the open swimming area clear means no fish gets cornered.

Recognising trouble early

Seriously Fish's warning about swim bladder and digestive problems means a gold balloon molly needs watching more closely than a normal-bodied sailfin. Most trouble gives early signs if you know what your fish looks like when it is well.

Swimming problems

Wikipedia's swim bladder disease article describes affected fish floating nose-down and tail-up, floating up to the surface or sinking to the bottom, with a changed swimming pattern. The causes it gives include physical abnormalities, inbreeding, overeating, constipation, low water temperature, bacterial infections and parasites. You cannot change your fish's skeleton, but you can control food, temperature and water quality.

Get to know how your fish moves when it is healthy. The warning sign is a change from that normal: a fish that now tilts, struggles to stay level or sits on the bottom.

Six things to look at every day

OATA's care sheet lists six things to watch: swimming behaviour, colour, temperament, breathing, appearance and feeding. In practice, at feeding time:

1. Swimming: level and controlled, or tilting and labouring?
2. Colour: steady gold, or suddenly faded or darkened?
3. Temperament: behaving as usual, or hiding and being chased?
4. Breathing: calm gills, or rapid breathing near the surface?
5. Appearance: fins spread, or clamped, torn, spotted or patchy?
6. Feeding: eating with interest, or spitting food out and ignoring it?

What to do

Test the water first, every time. Ammonia, nitrite, high nitrate or a cooler tank lie behind a large share of the problems keepers see, and they need a water change or a heater repair, not a medicine. For a fish that is struggling to swim, Wikipedia lists the usual measures: keep the tank very clean, raise the temperature slightly to help digestion, feed nutritious food, offer green peas, and separate the affected fish from the others. Peas suit a plant-eating molly well. For the separate tank, Wikipedia's advice is to keep it bare, without gravel, stones or ornaments, which also makes it easy to keep spotless and to see whether the fish is eating. If there is no improvement, ask an aquatic specialist or a vet who treats fish before using any medication.

How long they live

According to OATA, guppies and mollies can live several years in a well-matured aquarium with good water. Seriously Fish's warning about premature death in the balloon variety means you should not count on a balloon molly matching that. Careful keeping gives it the best odds.

Quarantine for newcomers

If you already keep fish, a separate quarantine tank lets you watch new arrivals for a few weeks before they join everyone else. It also lets you see how a gold balloon molly eats and swims without competition.

Pregnancy, fry and whether to breed them

Sailfin mollies are livebearers. Fertilisation happens inside the female, by way of the male's gonopodium, and the young are born live. Wikipedia notes that females store sperm and can give birth several times a year, so a female that has mated before may drop fry later even if she never meets one of your males.

The numbers, compared

Most of these sources agree on about four weeks. Seriously Fish's longer figure is the exception. Wikipedia ties brood size to a female's maturity and size, so a small balloon female is unlikely to reach the largest broods quoted for wild fish.

FishBase puts first maturity in wild sailfins at around 6.7 cm, within a range of 5 to 9.5 cm. That length belongs to full-bodied wild fish and does not map neatly onto a short balloon molly. Once your fish look grown, assume the females could be pregnant.

Raising fry

Seriously Fish calls sailfin molly fry relatively large and says they can eat brine shrimp nauplii, microworm or powdered flake straight away. It recommends a heavily planted breeding tank. Thick planting in the main aquarium, or a separate planted nursery, is the easiest way to bring a brood on.

Should you breed balloon mollies?

Our view is to think hard before setting out to. The balloon shape is inherited, and Seriously Fish ties it to swim bladder and digestive problems. If fry arrive anyway, plan homes for them early. Shops and clubs sometimes take healthy young fish, but none has to.

Unpacking and settling in

Before ordering, please read our delivery and live-arrival page. These are the points that matter most for a gold balloon molly.

Getting ready

The aquarium needs to be ready before the box is: filter running, water tested, temperature matched to the targets above. Someone has to be at the delivery address to take in the parcel, because it contains live animals. The confirmed delivery date and tracking come to you by email. In transit, your fish travels in an oxygen-filled bag in insulated packaging, with heat packs added when conditions call for them, carried by a tracked courier licensed to carry live animals.

Recording the unboxing

Begin a continuous video while the parcel is still sealed and keep recording, in the same take, as you open it, showing the fish inside the bag before the bag is opened. If any fish is dead, dying or clearly compromised on arrival, send that video with your order number to hello@tropicalfishco.co.uk on the day of delivery. Photographs on their own do not meet the policy. The fix is either a replacement with your next order or a refund for the affected fish, subject to the guarantee terms.

Into the aquarium

1. Float the unopened bag for 20 to 30 minutes to bring it to tank temperature.
2. Remember that floating equalises temperature, not pH or hardness. If your water differs a lot from the hard, alkaline conditions above, ask us for advice before going further.
3. Lift the fish across with a net.
4. Pour the transport water away, never into the aquarium.
5. Dim the lights and leave the fish in peace.

Week one

Over the first week, check breathing, appetite and behaviour every day, and feed sparingly. With a balloon molly, swimming is the extra thing to watch. Steady swimming and an interest in food mean it is settling. Struggling to stay level, or refusing food, means test the water at once and look more closely.

Further reading

These are the sources behind the facts on this page.

• FishBase species summary for Poecilia latipinna
• Seriously Fish species profile: the sailfin molly
• Wikipedia article on the sailfin molly
• Wikipedia on fancy mollies, with the gold and balloon types
• Genes (2019): loci behind dwarfism in the white sailfin molly
• OATA care sheet for guppies and mollies