Molly

Behaviour and habits

The shortfin molly is an active, hardy livebearer that browses constantly for algae and food and breeds readily. It is peaceful but can become nippy if kept in too few, and it is tolerant of a touch of salt, though it does not need it. It is one of the livebearers that most depends on hard, warm, alkaline water, and it is a constant grazer that needs vegetable matter in its diet to stay healthy and busy.

What to feed, and how often

It needs real vegetable matter: algae, blanched spinach, courgette or spirulina flake, plus a staple flake and occasional frozen food. Feed twice a day, lightly, and do not rely on dry food alone — mollies graze constantly and suffer without greens.

Water changes and maintenance

Change about 25% weekly in hard, warm, alkaline water, matched closely. Mollies suffer in soft, cold water, where they develop 'shimmies' and fungus, so keep the water hard, warm and clean and nitrate low.

Care and how easy it is

Hardy, but it needs harder and warmer water than most beginners expect, plus a vegetable-rich diet and a tank big enough for its size.

Lifespan

With good conditions and steady water quality, this species typically lives around 3–5 years in a home aquarium; some individuals live longer.

Common health problems

Its health comes down to water hardness — soft, cold or dirty water brings 'shimmies' and fungus, and freshwater ich is common when stressed.

If it gets sick

Check hardness and temperature first, fix the water and diet, and treat fungus or ich early, watching for a few days.