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Sailfin mollies are popular aquarium fish but have become a pest in some Queensland waterways due to people releasing them. You may keep sailfin mollies in an aquarium, but don't release them. Don't use them as bait, alive or dead. If you catch them in the wild, you must humanely kill them—don't return them to the water.
- Males grow to 15cm.
- Females grow to 10cm.
- Males have a large, sail-like fin, often tipped in black, that distinguishes this species.
- Head is flattened with an upturned mouth.
- Green, grey and black and many other colours.
- Speckled varieties are popular in aquariums.
- Lives in fresh and brackish water.
- Prefers marshes, lowland streams, estuaries, ponds and lakes that are heavily vegetated.
- Commonly found under aquatic vegetation where they hide from predators.
- Hardy, can withstand low oxygen levels and moderate salinity (saltiness).
- Native to North America.
- Introduced to many areas including Hawaii, Philippines, Canada, Singapore, New Zealand, Kenya, Columbia, Bahamas and Australia.
- Established in coastal drainages of South East Queensland—Hervey Bay, Burrum River and Brisbane River.
- Produces 10–100 live young after a gestation of about 28 days.
- Breeds in fresh or brackish water.
- In high populations, they can reach sexual maturity at smaller sizes, known as 'stunting'.
- Feeds mainly on algae but also eat insect larvae.
- A few countries have reported adverse ecological impacts after they introduced sailfin mollies.
- Competes with native fish for food and space.
- Dominates waterways due to high ability to reproduce and survive in habitats and water qualities that are not suitable for native fish.
- Often found in degraded waterways.
- Spread by people dumping aquarium contents in native waterways, and stocking backyard ponds prone to flooding.
- Don't dump your aquarium fish. Either kill them humanely or return them to pet shops.
- If you catch sailfin mollies in the wild, humanely kill them and do not return them to the water. Report all invasive fish captures through our online reporting form. Take photos, if possible.
- Fisheries Act 1994 and Fisheries Regulation 2008
- Grant, EM 1997, Grant's guide to fishes, EM Grant Pty Ltd, Brisbane
- Contact the Customer Service Centre
- FishBase—a global information system on fishes
- Last reviewed: 17 Dec 2018
- Last updated: 17 Dec 2018