Quick Stats
| Adult Size | 25 cm |
| Minimum Tank | 55 gal |
| Temperature | 22–30°C |
| pH Range | 6.0–8.0 |
| Hardness (GH) | 8–20 dGH |
| Difficulty | Easy |
| Temperament | Aggressive |
| Diet | Carnivore — pellets, frozen foods, earthworms, feeder shrimp |
| Schooling | Keep alone or with equal-sized aggressive species |
Tank Setup
The Jack Dempsey (Rocio octofasciata) requires a minimum tank size of 55 gal. For a species this size, a larger tank is always better — more water volume means more stable parameters and a healthier environment.
Water parameters should be maintained within the following ranges: temperature 22–30°C, pH 6.0–8.0, and hardness 8–20 dGH. These are relatively tolerant fish that adapt to a range of conditions.
Provide appropriate hiding places, a suitable substrate, and planted areas to match the natural behaviour of this species.
Tank Mates
Jack Dempsey are aggressive fish. Choose tankmates carefully — they may not be suitable for all community setups.
Compatible tank mates include: Oscar, Green Terror, Convict Cichlid, Large Plecos. Always ensure all species share similar water parameter requirements before mixing.
Schooling requirements: Keep alone or with equal-sized aggressive species.
Diet & Feeding
Jack Dempsey are Carnivore. Their diet should reflect their natural feeding habits.
Carnivore — pellets, frozen foods, earthworms, feeder shrimp
Feed small amounts 1–2 times daily. Only provide what the fish can consume within 2–3 minutes to prevent overfeeding and water quality issues. Supplement with live or frozen foods for optimal health and colour.
Common Health Issues
Like all aquarium fish, Jack Dempsey can be susceptible to common diseases including ich (white spot disease), fin rot, and bacterial infections. This species is generally hardy and disease-resistant when kept in good conditions.
Prevention is always better than treatment. Maintain stable water parameters, avoid overfeeding, quarantine new fish before adding them to the main tank, and perform regular water changes. A regular maintenance routine will prevent most health issues.
If disease does occur, isolate affected fish in a quarantine tank and treat appropriately. Always research medication compatibility before use — some treatments are toxic to invertebrates and scaleless fish.
Breeding
Breeding Jack Dempsey is possible in the home aquarium.
Provide appropriate breeding conditions — caves or hiding places for egg-laying species. Condition breeding pairs with high-quality foods before attempting to spawn them.
Many Jack Dempsey will breed readily without intervention. Be prepared to remove eggs or fry if you want to raise them — adult fish may eat their own young.
Frequently Asked Questions
What size tank does a Jack Dempsey need?
A Jack Dempsey needs a minimum tank size of 55 gal. However, larger is always better — more water volume means more stable water parameters and healthier fish.
Are Jack Dempsey easy to keep?
Jack Dempsey are rated as Easy difficulty. Beginners can keep them successfully with proper research and a cycled tank.
What do Jack Dempsey eat?
Jack Dempsey are Carnivore. Feed a varied diet including pellets, frozen foods, earthworms, feeder shrimp.
Can Jack Dempsey live with other fish?
Jack Dempsey are aggressive. Compatible tankmates include: Oscar, Green Terror, Convict Cichlid, Large Plecos. Always research compatibility before mixing species.