Compatibility Overview
Congo Tetra and Goldfish 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 | Congo Tetra | Goldfish | Verdict |
|---|---|---|---|
| Temperature | 72–79°F | 50–74°F | ⚠️ 72–74°F (narrow) |
| pH Range | 6.0–7.0 | 6.5–8.0 | ⚠️ 6.5–7.0 (narrow) |
| Temperament | aggressive | peaceful | ❌ Risk |
| Adult Size | 1.6 in | 12 in | ❌ 8× difference |
| Min. Group | 6+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Congo Tetra — Aquarium species
The Congo Tetra is a vibrant and active fish that thrives in a well-maintained freshwater aquarium. With its striking coloration and peaceful nature, it's a great addition to any community tank. This species is best kept in groups and requires a spacious tank with plenty of swimming space. They are known for their playful nature and can be seen darting aroun
Goldfish — Carassius auratus
Classic pond and aquarium fish that prefer cool water. Heavy waste producers that require robust filtration. Will eat small fish and shrimp.
Frequently Asked Questions
Can Congo Tetra live with Goldfish?
Generally not recommended. Congo Tetra and Goldfish 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 Congo Tetra and Goldfish together?
A minimum of 100 gallons is recommended for keeping Congo Tetra and Goldfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Congo Tetra and Goldfish?
72–74°F (narrow)
Is a Congo Tetra aggressive toward a Goldfish?
Congo Tetra is aggressive and Goldfish is peaceful. These animals require different water types and cannot share one aquarium.
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 | 29/100 |
| Ph | 50/100 |
| Temperament | 30/100 |
| 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 | 220 gal | Best when keeping larger schools or reducing territorial pressure. |