The short answer
Keep platies in a group of 5 or more. They aren’t obligate schoolers like tetras, but they’re sociable and calmer in numbers, and a small group looks far better than a pair. If you keep both sexes, use 2–3 females per male so males don’t harass a single female. Platies are peaceful, hardy and easy — a great beginner livebearer.
Group size and the sex ratio
A group of five or more platies settles quickly and stays active in the open. The main thing to get right is the male-to-female ratio. Male platies court females persistently, so with a single female per male she’s chased constantly. Keeping more females than males spreads that attention and keeps everyone relaxed. If you’d rather avoid fry altogether, keep an all-male or all-female group — colour without a population boom.
Sensible platy stocking
- 5–6 platies, 2 males to 4 females, in a 60 litre+ tank
- An all-male group for colour without constant fry
- Platies alongside compatible livebearers like mollies, swordtails and guppies
- A peaceful bottom group such as corydoras underneath
Avoid fin-nippers and overstocking — platies are peaceful and do best in calm company. A few floating or bushy plants also give fry and females somewhere to shelter, which keeps the whole group relaxed.
Before you stock
Cycle the tank first — see how to cycle an aquarium. Read the full platy care guide, nail the ratio with the livebearer male-to-female ratio, and plan the wider stock using how to plan a community tank. For the tank itself, see the best 60 litre aquariums.