Compatibility Overview
Oscar and Red Eye Tetra 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 | Oscar | Red Eye Tetra | Verdict |
|---|---|---|---|
| Temperature | 74–81°F | 72–79°F | ✅ 74–79°F |
| pH Range | 6.0–8.0 | 6.0–7.0 | ✅ 6.0–7.0 |
| Temperament | aggressive | aggressive | ❌ Risk |
| Adult Size | 14 in | 1.6 in | ❌ 9× difference |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
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.
Red Eye Tetra — Aquarium species
The Red Eye Tetra is a popular freshwater fish known for its vibrant red eyes and sleek, silver body. They are generally peaceful and can be kept in a community tank with other non-aggressive species. Their moderate activity level makes them suitable for a variety of aquarium setups. With proper care, they can live up to 5 years.
Frequently Asked Questions
Can Oscar live with Red Eye Tetra?
Generally not recommended. Oscar and Red Eye Tetra 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 Oscar and Red Eye Tetra together?
A minimum of 100 gallons is recommended for keeping Oscar and Red Eye Tetra together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Oscar and Red Eye Tetra?
74–79°F
Is a Oscar aggressive toward a Red Eye Tetra?
Oscar is aggressive and Red Eye Tetra is aggressive. The adult size gap creates a meaningful predation risk.
Related Compatibility Guides
Compatibility score breakdown
The overall score is weighted across water chemistry, behavior, adult size, swimming zone, and social needs. A score is a planning aid—not a guarantee for individual fish.
| Factor | Score |
|---|---|
| Temperature | 71/100 |
| Ph | 100/100 |
| Temperament | 12/100 |
| Adult Size | 8/100 |
| Swim Zone | 68/100 |
| Social Needs | 92/100 |
Tank size scenarios
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 100 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 150 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 180 gal | Best when keeping larger schools or reducing territorial pressure. |