Medium
Oscar
Astronotus ocellatus
Jack Dempsey
Rocio octofasciata
Reviewed for accuracy · Last updated Jan 2, 2026, 3:44 PM
Territorial cichlid known for bold displays, pair bonding, and intense aggression during spawning, especially.
Key Information
Water Type
Freshwater
Temperament
Very Aggressive
Care Level
Medium
Minimum Tank Size
53 gal (200 L)
Maximum Size
10 in (25 cm)
Lifespan
8–12 years
Diet
Omnivore
Migration
Resident
Jack Dempsey Behavior and Compatibility
Jack Dempsey cichlids are best kept with robust species. Tank mates must tolerate aggression and similar water parameters. Size and temperament compatibility are critical.
Suitable companions include large Central American cichlids. Fast, sturdy catfish can work in large tanks. Avoid small or passive species.
Overcrowding increases territorial disputes significantly. Provide visual barriers to reduce line of sight aggression. Monitor interactions closely.
Breeding pairs become highly intolerant of other fish. Temporary separation may be required.
Best Tank Mates for Jack Dempsey
Jack Dempsey Tank Setup and Care
Jack Dempsey cichlids require spacious aquariums with stable conditions. Strong filtration is essential due to their size and waste output. Water quality must be kept consistent to reduce stress.
Rocky structures and caves help establish territories and reduce conflicts. Substrate should allow natural digging behavior without sharp edges. Lighting can be moderate, avoiding overly bright setups.
Regular water changes are critical for long term health. Heaters must maintain stable tropical temperatures. A covered tank is recommended due to sudden bursts of activity.
These fish thrive when environmental stressors are minimized. Calm surroundings and predictable maintenance routines are ideal.
Jack Dempsey Diet and Feeding
Jack Dempsey cichlids are opportunistic omnivores in captivity. They accept pellets, sticks, and frozen foods readily. A protein rich diet supports growth and coloration.
Offer high quality cichlid pellets as a daily staple. Supplement with frozen shrimp, worms, or krill weekly. Vegetable matter should be included occasionally.
Avoid overfeeding to prevent obesity and water pollution. Feed once or twice daily in controlled portions. Remove uneaten food promptly.
Diet variety improves immune response and vitality. Consistent feeding schedules reduce aggression.
Jack Dempsey Breeding and Reproduction
Jack Dempsey cichlids are substrate spawners. Pairs form strong bonds before breeding begins. Flat rocks or caves are chosen for egg laying.
Both parents participate in egg and fry protection. Aggression increases dramatically during this period. Tank mates are often attacked.
Eggs hatch within a few days under warm conditions. Fry are moved to pits dug in the substrate. Parents guard them intensely.
Dedicated breeding tanks improve survival rates. Stable water quality is essential.
Jack Dempsey Water Parameters
72–82 °F (22–28 °C)
6.5–7.5
6–15 dGH
1.000–1.002 SG
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Frequent Questions About Jack Dempsey
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What tank size is recommended for Jack Dempseys?
The Jack Dempsey requires a minimum tank size of 55 gallons for a single adult, with larger volumes recommended for pairs or community setups. Adequate space helps reduce territorial aggression and supports stable water parameters.
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What is the typical behavior of Jack Dempsey?
The Jack Dempsey is known for territorial and assertive behavior, especially during breeding periods. While not constantly aggressive, it may display dominance toward smaller or passive fish.
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What diet is best for Jack Dempseys long-term health?
The Jack Dempsey thrives on a varied omnivorous diet that includes high-quality cichlid pellets, frozen foods, and occasional live prey. A balanced diet supports coloration, immune function, and proper growth.
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Does Jack Dempsey fish school or prefer groups?
The Jack Dempsey is not a schooling fish and does not require group living. It is best kept alone, as a bonded pair, or with carefully selected tank mates to prevent stress and aggression.
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Is Jack Dempsey fish suitable for community aquariums?
The Jack Dempsey can be kept in semi-aggressive community aquariums with robust and similarly sized species. Compatible tank mates may include the Oscar Fish, Green Terror, or Firemouth Cichlid, provided the aquarium is spacious and well-structured.
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What care considerations are important for beginners keeping Jack Dempsey fish (Rocio octofasciata)?
The Jack Dempsey requires stable tropical water conditions, efficient filtration, and regular maintenance. Compared to species like the Blue Acara or Convict Cichlid, it demands more attention to tank size and compatibility planning.
