Sailfin molly

Behaviour and habits

The sailfin molly is a big, showy livebearer whose males raise a tall, sail-like dorsal fin, and it is one of the larger common livebearers. It is peaceful but large and active, swimming at every level, and like other mollies it breeds readily, so keep more females than males. It is a grazer that browses algae and needs vegetable matter, and it is far happier in hard, warm water than in soft, cool conditions.

What to feed, and how often

Flake plus blanched greens and frozen food; feed twice a day, lightly. Vegetable matter is especially important for mollies, which graze constantly and need greens in the diet; greedy eating plus too little greenery is a common cause of problems.

Water changes and maintenance

Change about 25% weekly in hard, warm water, matched closely. Soft or cold water brings 'shimmies' and fungus, so keep the water hard, warm and clean, and keep nitrate low.

Care and how easy it is

Needs hard, warm water and a big tank for its size; hardy once the conditions suit it, but not a fish for soft, cool water.

Common health problems

Sensitive to soft, cold water — prone to 'shimmies' and fungus there.

If it gets sick

Keep the water hard and warm, offer greens, and treat early if fungus or twitching appears.