Fish
Electric Blue Jack Dempsey
Rocio octofasciata var.
Origin: Central America — Mexico, Belize, Guatemala, Honduras (captive-bred mutation)
Also known as: Electric Blue Dempsey, EBJD, Blue Dempsey
Fact sheet
- Size
- 20 cm
- Lifespan
- 10 years
- Minimum tank size
- 200 L
- Temperature
- 26–30 °C
- pH
- 7–8
- Hardness GH
- 5–15 °dH
- Temperament
- Aggressive
- Social behavior
- In pairs
- Swimming zone
- Middle, Bottom
- Diet
- Carnivore
- Jumps out
- No
- Eats plants
- No
Varieties
Overview
The Electric Blue Jack Dempsey is a striking recessive colour mutation of the Jack Dempsey cichlid (Rocio octofasciata), first discovered among hobbyists in the 1980s. Unlike the wild type which displays iridescent blue speckling on a dark body, the Electric Blue variant exhibits an intense metallic blue covering almost the entire body. Named after boxer Jack Dempsey for its pugnacious nature, the Electric Blue form is considerably calmer than its wild-type counterpart while still retaining a bold personality. The species is native to warm, murky lowland waters in Central America from southern Mexico through Belize, Guatemala, and Honduras. It is an active, curious fish that makes for an engaging aquarium specimen. Care requires some experience due to sensitivity to water quality and territorial tendencies during breeding.
Appearance
The Electric Blue Jack Dempsey has a compact, laterally compressed oval body reaching 15–20 cm in males and slightly less in females. The body is dominated by a brilliant electric-blue metallic sheen that intensifies with age and good condition. The dark vertical banding typical of the wild-type form is mostly absent or greatly reduced. Males are larger with elongated, pointed dorsal and anal fins, while females have shorter, more rounded fins and may show slightly less vibrant colouration.
Care
A minimum tank footprint of 120 × 45 cm (approximately 240 litres) is required for a single pair. A soft sand or fine gravel substrate is preferred since they enjoy digging. Furnish with driftwood, large rocks, and robust plants such as Anubias or Java Fern. Efficient filtration with moderate flow is essential. Maintain water at 22–28 °C, pH 6.5–8.0, and hardness 5–20 dGH. Weekly water changes of 25–30% are recommended. Never add this species to immature aquaria.
Feeding
An eager omnivore, the Electric Blue Dempsey thrives on high-quality sinking cichlid pellets as a staple. Supplement with frozen or live foods including bloodworm, brine shrimp, Mysis shrimp, daphnia, and chopped shrimp or mussel. Flake food is also accepted. Feed twice daily in small portions, avoiding overfeeding. Varied nutrition helps maintain vibrant colouration.
Compatibility
Semi-aggressive to aggressive, particularly during spawning. Not suitable with small fish, which may be eaten. Good tankmates include larger Central American cichlids, armoured catfish (Pleco), and silver dollars. Avoid keeping with similarly shaped cichlids that may trigger territorial conflict. Best kept as a single specimen or a bonded pair in a species or semi-species setup.
Breeding
Breeding in captivity is challenging due to the genetics of the mutation — most Electric Blue individuals are homozygous for a recessive allele and show reduced fertility or are infertile. To produce Electric Blue offspring, cross an Electric Blue fish with a heterozygous carrier (a standard Jack Dempsey carrying one eb allele). Spawning is substratal: eggs are laid on a flat stone or in a pit dug in the substrate. Both parents guard eggs and larvae vigorously. Eggs hatch in approximately 3 days and fry become free-swimming in 5–7 days. Only around 25% of offspring from such a cross will display the Electric Blue phenotype.
Fun facts
The Electric Blue mutation is entirely captive-bred — this colour form does not exist in the wild. Despite being calmer than the standard Jack Dempsey, Electric Blue individuals still become highly territorial and aggressive when spawning. The Jack Dempsey (and its variants) has established invasive populations in Australia, the USA, and Thailand after aquarium releases.