Jack Dempsey
Rocio octofasciata
The Heavyweight Brawler of Central America (20-25 cm / 8-10 inches). Named after the legendary 1920s boxing champion, this fish boasts a bulldog-like face, a thickly muscled body, and a famously terrible temper. But it is an absolute visual showstopper: a dark, almost pitch-black body heavily armored with hundreds of massive, blindingly bright neon cyan, gold, and emerald 'spangles' (scales) that look like glowing sequins. He destroys tanks, digs massive craters, and will relentlessly bully anything that gets in his way.
22 - 26 °C
6.5 - 8
Freshwater
Bottom and middle
25 cm
>= 300 L
>= 1
5 - 20 dGH
2 - 10 dKH
95 - 400 ppm
148 - 625 uS/cm
Species description
Care, breeding and tankmates
Geographic Origin and Distribution
Origin
Fish profile
- Temperament
- Semi-aggressive
- The Jack Dempsey is well known for its belligerent and aggressive temperament. It actively and aggressively defends its chosen territory. Heavy decoration can help manage aggression by breaking lines of sight.
- Diet
- Omnivore
- The Jack Dempsey is primarily carnivorous but accepts a variety of foods. High-quality cichlid pellets should form the staple diet. Supplement with live or frozen foods like bloodworms and brine shrimp.
- Life expectancy
- 10-15 years
- Under optimal captive care, the Jack Dempsey cichlid typically enjoys a lifespan of 10 to 15 years. Achieving this longevity depends on providing a large aquarium with excellent filtration and stable water chemistry, as they are sensitive to poor water quality and organic waste buildup. A balanced diet containing high-quality proteins and essential vitamins helps prevent nutritional deficiencies and strengthens their immune system. Minimizing stress by providing ample hiding spaces and avoiding overly aggressive tankmates will also extend their lifespan.
- Adult size
- 25 cm
- The catalog's scalar value is 25 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 25 cm for this species, recorded as total length (TL). The taxonomic record consulted is Rocio octofasciata (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Pair
- They are best kept as a single male-female pair in most setups. Keeping multiple males usually leads to severe aggression and territorial disputes. Carefully monitor the female for signs of harassment.
- Feeding frequency
- Twice daily
- Adults should be fed once a day to prevent obesity. Juveniles require two to three smaller meals daily to support growth. Avoid overfeeding to maintain optimal water quality.
- Bioload
- This species generates a significant bioload due to its size and hearty appetite. Powerful filtration is required to process the heavy waste output. Regular large water changes are also essential to maintain good water quality.
- Flow
- Stagnant
- It prefers a moderate flow in the aquarium environment. Strong currents are not necessary but good circulation is. Ensure there are calmer areas for the fish to rest comfortably.
- Reproduction
- Oviparous
- These cichlids are substrate spawners and excellent parents. They become highly aggressive when breeding and raising fry. Flat rocks or large slate pieces should be provided as spawning sites.
- Compatibility & tankmates
- It is highly aggressive and territorial in nature. It should only be kept with other large, robust cichlids. Small tankmates will likely be bullied, injured, or eaten.
- Tank level
- Middle/Bottom
- It mainly inhabits the middle and bottom levels of the tank. It likes to stay near caves and structural cover. It rarely swims at the very top of the water column.
Scientific Parameters & Models
Window to the official scientific data of the species
- Trophic level
- 3.5 ± 0.51 se
- Resilience
- High (less than 15 months)
- Phylogenetic uniqueness (PD50)
- 0.5625
- Bayesian Length-Weight
- a = 0.02692, b = 3.02
- VulnerabilityLow vulnerability (15 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.























































