What size tank does a Jack Dempsey need?

Jack Dempsey needs a minimum of 75 gallons, with 113 gallons recommended. They are middle swimmers.

Is Jack Dempsey good for beginners?

Jack Dempsey is rated "intermediate" difficulty (2/5). Great for beginners.

What fish are compatible with Jack Dempsey?

Jack Dempsey is aggressive. Compatible tank mates include other aggressive fish with similar water parameters (pH 6.5-7.5, temp 72-82°F). Give adequate territory space.

Jack Dempsey

Rocio octofasciata

Family: Cichlidae • Origin: Various

Jack Dempsey (Rocio octofasciata) is a aggressive cichlid reaching 10 inches. Can be kept singly. Minimum tank size: 75 gallons.

Min Tank

75 gal

Max Size

10"

Temperature

72-82°F

6.5-7.5

Lifespan

15 years

School Size

Solo OK

Swim Level

middle

Hardness

5-15 dGH

aggressiveintermediatecarnivore

Is Jack Dempsey Right for Your Tank?

Jack Dempsey is an excellent choice for beginners — rated "intermediate" difficulty (2/5). They're hardy, forgiving of minor water parameter fluctuations, and generally easy to feed. They need at least 75 gallons — a mid-size tank commitment. Plan your space accordingly.

Jack Dempsey is aggressive and best kept alone or with other robust species that can hold their own. Not suitable for peaceful community tanks. They are territorial — provide adequate hiding spots and maintain enough space to reduce aggression. Expected lifespan: 15 years with proper care.

Common Mistakes with Jack Dempsey

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Relying on a heater without a thermometer

Jack Dempsey needs 72–82°F. Heaters malfunction or drift over time — always use a separate thermometer to verify. Temperature swings of even 3–4°F can trigger stress and disease, particularly ich.

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Putting them in a tank under 75 gallons

Many beginners underestimate tank size needs. Jack Dempsey requires at least 75 gallons — ideally 113. Cramped tanks lead to stunted growth, aggression, and poor water quality.

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Housing with peaceful nano fish

Jack Dempsey is aggressive and territorial — small, peaceful species like neon tetras, endlers, or celestial pearl danios will be stressed, bullied, or eaten. Choose tank mates that can hold their own.