Jack Dempsey

Rocio octofasciata

Also known as: Dempsey, Electric blue Jack Dempsey

Water Parameters

• Temperature: 22–28°C
• pH: 6.5–8
• Hardness (GH): 89–322 ppm (5–18 dGH)

Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.

Care Summary

A stocky, powerful Central American cichlid whose adults are spectacularly studded with iridescent blue-green spangles over a dark body, and whose temperament earned it the name of a heavyweight champion. It is hardy, intelligent, and long-lived, but it is a real bruiser, territorial and aggressive in a way that surprises keepers who bought a small, drab juvenile, so it suits a single fish, a (closely-monitored) pair, or a tough cichlid community in a large tank. It will eat smaller tankmates and redecorate enthusiastically. A selectively-bred electric-blue form is widely sold and is a touch less aggressive but more delicate. For a keeper with the space and the right expectations, a striking and rewarding large cichlid.

Tankmates

Named after the heavyweight boxer for good reason: the Jack Dempsey is a genuinely aggressive, territorial cichlid, especially once paired and breeding, and it is not a community fish. The realistic options are a single specimen, a carefully-watched bonded pair in a species tank, or a robust setup with other tough, similarly-sized cichlids and large armoured catfish that can stand their ground. It will eat any fish small enough to swallow and dig and rearrange the tank to its own taste, so use heavy hardscape and sand. Tolerant of hard Australian tap water.

Compatible with

• Common Pleco
• Synodontis Catfish
• Silver Dollar
• Bristlenose Pleco

Avoid keeping with

• Betta
• Neon Tetra
• Guppy
• Angelfish
• Cherry Shrimp
• German Blue Ram
• Keyhole Cichlid

Common Problems

• serious territorial aggression, especially when breeding
• predation on smaller tankmates
• digging and uprooting decor and plants
• ich and hole-in-the-head with poor water quality

Sources: seriouslyfish.com, fishbase.org · Last updated: 2026-06-20