Poecilia reticulata: living card for the guppy

Poecilia reticulata (guppy) is one of the most frequent fish in the ornamental trade. Treating it as disposable beginner material is the mistake.

Quick read

• Type: tropical livebearer.
• Aquarium: stable planted tank with moderately hard water and room for a group.
• Indicative temperature: 22-26 C.
• pH: 7.0-8.0.
• Hardness: moderate to hard.
• Base volume: 60 L for a small group with breeding margin.
• Feeding: omnivorous, with fine plant matter and small protein foods.
• Difficulty: low-medium; the real difficulty is population control.

What to check before buying

Check for a straight spine, steady swimming, no sunken belly, and no white spots or clamped fins. Heavily selected lines may be more fragile.

Before buying, confirm that the aquarium is cycled, the group size or pair plan makes sense, and the setup runs at the species’ real temperature.

Aquarium design

Use dense plants, open zones, and mature filtration. If males and females are together, plan what to do with fry before they appear.

Use the card as a baseline, then watch the fish. Loss of colour, constant hiding, or all-day competition calls for a design correction before a chemical fix.

Working parameters

Guppies do better in stable, mineralized water than in forced very soft water. Do not compensate poor genetics with random salts.

Treat these ranges as a working zone, not permission to swing parameters. Rapid changes, immature aquariums, and incompatible species cause most problems.

Compatibility and warning

It works with peaceful fish from similar water, but not with fry predators if breeding is desired or with tail-nipping species.

Progressive wasting, clamped fins, and serial deaths often point to stress, poor sourcing, or an overloaded aquarium.

Reference sources

FishBase for taxonomy and distribution; NOAA/University of Florida historical ornamental-trade data for frequent market species; Aquarium Co-Op and specialist aquarium guides for practical husbandry ranges.