Can Goldfish live with Jack Dempsey?
Case-by-case. Watch group sizes, tank size, and feeding zones.
Why Goldfish and Jack Dempsey Don't Make an Easy Pair
They can coexist, but you need to manage the setup carefully. The temperature margin is tight — only 2°F of safe overlap, which leaves little room for thermostat drift.
Goldfish
Carassius auratus
| Adult Size: | 10.0" |
| Temperament: | peaceful |
| Min Tank: | 30 gal |
| Temperature: | 62-74°F |
| pH Range: | 6.5-7.5 |
Jack Dempsey
Rocio octofasciata
| Adult Size: | 10.0" |
| Temperament: | aggressive |
| Min Tank: | 55 gal |
| Temperature: | 72-82°F |
| pH Range: | 6.5-8.0 |
Water Parameter Overlap
| Parameter | Goldfish | Jack Dempsey | Overlap |
|---|---|---|---|
| Temperature | 62-74°F | 72-82°F | 2°F ✓ |
| pH | 6.5-7.5 | 6.5-8.0 | 1.0 ✓ |
Compatibility Breakdown
Temperament Match: peaceful + aggressive. One aggressive → predation/nipping risk.
Score: 55.0/100 (GOOD ≥80, CAUTION ≥50, RISKY <50).
🔧 Tank Setup Requirements (for Both)
- Minimum tank: 55 gallons — sized for the larger fish in the pair.
- Temperature: keep it between 72°F and 74°F.
- pH: maintain 6.5 – 7.5.
- Hiding spots: essential for Goldfish — caves, plants, or driftwood to retreat when feeling stressed.
- Water changes: 25% weekly minimum. Two species mean double the bioload.
🔧 Tank Stocking Calculator
Enter tank size to calculate safe stocking levels:
Recommended Equipment
Based on tank size 55+ gallons:
Floating pellet for medium to large cichlids
Explore Related Checks
See what else works with these fish:
Accuracy note: This tool uses expert rules + FishBase.org data. Individual fish behavior varies — a peaceful individual Goldfish may act differently from its species average. Always observe, quarantine new arrivals for 2-4 weeks, and avoid overcrowding. If a pairing says CAUTION, start with a smaller group and a lid.