Guppies (Poecilia reticulata) are one of the most popular freshwater fish in the world, and for good reason: they are colourful, hardy, active, and beginner-friendly. But "easy" does not mean "careless." Poor water quality and overcrowding kill more guppies than anything else.
Quick-Reference Care Card
Tank Setup
A 40-litre tank is the practical minimum for a small guppy group. Guppies are active swimmers and do best with a longer footprint rather than a tall, narrow tank. Use a gentle filter: a sponge filter or low-flow HOB is ideal, as strong currents stress their long fins.
Add plants (real or silk) for cover, especially if you keep males and females together. Dense planting also gives fry a chance to survive. A lid is essential: guppies are notorious jumpers.
If you do not want to deal with constant breeding, keep only males. They display their best colours without the stress of reproduction and will not overpopulate your tank.
Water Parameters
Guppies prefer slightly hard, slightly alkaline water. They are very tolerant of a wide range, but stability matters more than hitting exact numbers. A sudden shift of 1 pH unit will stress or kill fish even if both values are within the "acceptable" range.
Key requirements: temperature 24-26 °C is the sweet spot; pH 7.0-7.5; hardness 8-12 dGH. Soft, acidic water (below pH 6.5) causes fin rot and reduced colour over time. Do weekly 25-30% water changes in a cycled tank.
Feeding
Guppies are omnivores and easy to feed. A quality micro-pellet or flake as a base, supplemented 2-3 times a week with frozen/live food (daphnia, baby brine shrimp, micro worms), keeps them healthy and showing their best colours. Feed small amounts twice a day, only what they consume in 2 minutes. Overfeeding pollutes the water fast in a small tank.
Compatible Tank Mates
| Species | Compatibility | Notes |
|---|---|---|
| Neon / cardinal tetras | Good | Same temperature range, peaceful |
| Corydoras catfish | Good | Bottom dwellers, ideal companions |
| Platies / mollies | Good | Similar water needs |
| Endlers livebearers | Caution | Will hybridise with guppies |
| Betta fish | Avoid | Betta attacks male guppy fins |
| Tiger barbs | Avoid | Notorious fin nippers |
Breeding
Guppies breed prolifically. Females are livebearers: they give birth to free-swimming fry every 25-30 days. A single female can store sperm for multiple broods after a single mating. If you want fry to survive, add dense floating plants (java moss, hornwort) or move the pregnant female to a separate tank before birth. Males harass gravid females constantly; a ratio of 1 male to 2-3 females reduces stress.
An unchecked colony can go from 6 fish to 60+ in three months. Plan what to do with excess fish before you start mixing sexes.
Common Health Issues
Ich (white spot): caused by temperature fluctuations. Raise temp to 28 °C gradually and treat with a copper-based medication. Fin rot: usually poor water quality. Improve filtration and do more frequent water changes. Wasting / swim bladder issues: often genetic in fancy strains. Ensure varied diet and avoid overfeeding.
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