Compatibility Overview
Guppy and Oscar are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
| Factor | Guppy | Oscar | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 74–81°F | ✅ 74–81°F |
| pH Range | 6.8–8.5 | 6.0–8.0 | ✅ 6.8–8.0 |
| Temperament | peaceful | aggressive | ❌ Risk |
| Adult Size | 2.5 in | 14 in | ❌ 6× difference |
| Min. Group | 3+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Guppy — Poecilia reticulata
Hardy and colourful livebearers. Males' long flowing tails make them targets for fin-nipping species. Very prolific breeders.
Oscar — Astronotus ocellatus
Intelligent but aggressive cichlids that will eat any fish small enough to fit in their mouth. Require large tanks (75+ gallons) and robust tank mates.
Frequently Asked Questions
Can Guppy live with Oscar?
Generally not recommended. Guppy and Oscar are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
What tank size do I need for Guppy and Oscar together?
A minimum of 100 gallons is recommended for keeping Guppy and Oscar together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Guppy and Oscar?
74–81°F
Is a Guppy aggressive toward a Oscar?
Guppy is peaceful and Oscar is aggressive. Oscars will eat adult guppies.