Platy
Xiphophorus maculatus
- Care level
- Beginner
- Adult size
- 4–5 cm
- Minimum tank
- 55 litres
- Temperature
- 20–26 °C
Species profile
Molly
Poecilia sphenops
Common names: Molly, Common Molly, Black Molly, Short-Finned Molly
Recognized speciesLivebearers
Adult size
Up to 8 cm
Typical adult length 6–8 cm.
Up to 8 cm
Countries of origin
Good fit for your tank?
Good fit for
- A hard-water aquarium with other livebearers
- A keeper who has alkaline tap water
- A planted tank that has some algae to graze
Think carefully if
- Your water is soft or acidic
- You keep tetras or other soft-water species
- You have a small tank or no plan for fry
A hardy, algae-grazing livebearer from Central America. Mollies need hard, alkaline water and more room than most small livebearers, and they do poorly in soft-water community tanks.
Appearance and Identification
A stocky, broad-tailed fish in many colours, including solid black, white, gold, dalmatian, and sailfin-type forms. Males have a gonopodium and often taller dorsal fins.
Trade mollies are often hybrids, so the species label is not always exact. Balloon mollies are bred with a deformed spine and are prone to swimming and digestive problems.
Males are smaller and more colourful with a gonopodium. Females are larger and rounder.
Tank Requirements
- Suggested filter
- About 320–400 litres an hour
- Suggested heater
- About 75–125 W for this tank
- Minimum tank volume
- 80 litres
- Minimum tank length
- 90 cm
- Minimum group size
- 3
- Recommended group size
- 6
- Activity level
- Active
- Flow preference
- Low to moderate
- Planting preference
- Moderately planted
- Hiding places
- Yes
- Lid recommended
- Yes
- Jumping risk
- Moderate
Provide strong filtration, algae-covered surfaces to graze, and dense plants for females and fry. Mollies produce a lot of waste for their size, so regular water changes matter.
Behaviour and Tankmates
Peaceful and active, grazing almost constantly. Males follow females persistently, so females need cover.
Keep several females for each male. Fish are peaceful only with tankmates that tolerate the same hard water.
Males may chase each other, but this is rarely serious when there are enough females and cover.
Suits other livebearers, some rainbowfish, and hard-water-tolerant barbs and tetras. It is not a good fit for a soft-water community. Adults may eat shrimplets.
Water Parameters
Hard, alkaline water is the key requirement. Mollies do not need salt if the water is hard enough, although some line-bred fish come from brackish farms, so ask about the seller's water.
Parameter caveat
Keep the water hard and alkaline. Soft, acidic water is a common cause of poor health in livebearers.
Feeding
- Diet types
- Algae Grazer, Herbivore, Omnivore
- Feeding frequency
- Once or twice daily
- Preferred foods
- Spirulina or vegetable flakeShould be a main part of the diet, not an occasional extra.
- Blanched spinach or courgetteOffer once or twice a week, and remove leftovers within a few hours.
- Small granules plus frozen daphnia or brine shrimpProvides protein, especially for growing fish and gravid females.
An omnivore with a strong need for plant matter, and it spends much of the day grazing algae.
Algae in the tank helps but is not enough by itself. Feed plant matter daily.
Breeding
- Breeding type
- Livebearer
- Breeding difficulty
- Easy
- Brood or egg count
- Up to 120 live young per brood
- Parental care
- None
- Baby foods
- Newly hatched brine shrimpLivebearer fry are born large enough to take this straight away, and it gives the fastest growth.
- Finely crushed flakeEasy and widely accepted. Feed small amounts several times a day.
- MicrowormsUseful for the smallest fry and for those feeding near the floor of the tank.
A livebearer that breeds easily in suitable water. Gestation is about 8 weeks, with broods of up to 120 fry. Keep several females per male, and move a gravid female to a separate tank to give birth, since adults eat their young.
Habitat and Origin
- Geographic origin
- Captive Bred, Central America, Colombia, Curaçao, El Salvador, Honduras, Mexico, Nicaragua, South America, Venezuela
- Natural habitat
- Estuary, Freshwater Stream, Vegetated Shoreline
- Aquarium contexts
- Breeding Aquarium, Planted Aquarium
- Audience level
- Beginner
Classification
- Profile type
- Recognized species
- Genus
- Poecilia
- Family
- Poeciliidae
- Species group
- Fish, Livebearers
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Swordtail
Xiphophorus hellerii
- Care level
- Beginner
- Adult size
- 10–14 cm
- Minimum tank
- 150 litres
- Temperature
- 16–28 °C
Tequila Splitfin
Zoogoneticus tequila
- Care level
- Intermediate
- Adult size
- 6 cm
- Minimum tank
- 81 litres
- Temperature
- 17–27 °C
Tiger Teddy Livebearer
Neoheterandria elegans
- Care level
- Intermediate
- Adult size
- 2.5 cm
- Minimum tank
- 12 litres
- Temperature
- 24–30 °C