The short answer
Keep 2 to 3 female guppies for every male. Male guppies court and chase females almost constantly, so a lopsided ratio wears a single female out. Spreading several females per male means no individual is harassed non-stop, which keeps the whole group healthier and calmer. If you’d rather skip fry and squabbling entirely, keep an all-male group instead.
Why the ratio matters
Male guppies are relentless suitors — they pursue females almost every waking hour. With one female per male, she gets no break; the constant chasing stresses her, interrupts feeding and can shorten her life. Keeping two or three females per male dilutes that attention across the group so each female gets rest. It’s not about breeding numbers; it’s about welfare. The same logic applies to mollies, platies and swordtails.
Getting the group right
- Breeding colony: 1 male + 2–3 females (expect fry quickly)
- Colour, no fry: an all-male group of guppies
- Never: a single male with a single female — she’ll be harassed constantly
- Add cover — plants like guppy grass give females places to retreat
Whichever you choose, don’t overstock: guppies breed fast and the bioload creeps up.
Before you stock
Cycle the tank first — see how to cycle an aquarium. Read the full guppy care guide, work out numbers with how many guppies in a 60 litre tank, and plan the wider community via how to plan a community tank. For a suitable tank, see the best 60 litre aquariums.