The Electric Blue Jack Dempsey is one of the bluest tropical fish, and it is definitely one of the most beautiful!

The Electric Blue Jack Dempsey cichlid Rocio octofasciata cf. (previously Cichlasoma octofasciatum) is considered to be one of the most beautiful freshwater aquarium fish. The adult displays a magnificent blue coloration, and is definitely one of the ‘bluest’ freshwater fish in the hobby. It has a dark brown background that is covered with brilliant metallic and iridescent blue flecks. It will reach a maximum length of a little more than 8″ (20 cm), or slightly smaller than its genetic progenitor,the Jack Dempsey.These fish are also called the Blue Dempsey, Electric Blue Dempsey, and Jack Dempsey Neon Blue.

This dazzling fish is a naturally occurring variant of the Jack Dempsey. According to popular rumor, fry which displayed the bright blue coloring of the Electric Blue Jack Dempsey were considered to be malformed and runtish and were discarded by their keepers as inferior specimens. Fortunately for those hobbyists who appreciate the stunning coloration of these fish, and for the hobby in general, this archaic and incorrect view has been largely discarded and these fish are now being actively bred and developed in captivity. Though the Blue Dempsey is relatively easy to breed, it does take a considerable amount of time, luck, and a well designed aquarium set up, so these fish are rather rare and quite a bit more expensive than many other tropical fish, include the Electric Blue Jack Dempsey’s progentitor species, the Jack Dempsey.

The Blue Dempsey is a bit more delicate than its parentage. But just like its progenitors, it likes a tank bottom of fine sand to burrow in and create nests out of. It also needs plenty of hiding places among rocks and wood, and a cover of floating plants. However they will enjoy snacking on any plants in the aquarium, so it is reccommended to monitor the status of any plants sharing the tank with a Blue Dempsey.

This cichlid, true to its family, tends to be semi-aggressive and will appreciate being kept in a large aquarium with similarily sized and tempered tankmates. That being said, it generally is not quite as aggressive as many cichlids and can be shy at times. Thus, it is best to either keep it singly or in a large group with only a few other tankmates.

Electric Blue Jack Dempsey

Scientific Classification

Kingdom:Animalia
Phylum:Chordata
Class:Actinopterygii
Order:Perciformes
Family:Cichlidae
Genus:Cichlasoma
Species:octofasciatum

Electric Blue Jack Dempsey – Quick Aquarium Care

Aquarist Experience Level:Beginner
Aquarium Hardiness:Very hardy
Minimum Tank Size:40 gal (151 L)
Size of fish – inches8.0 inches (20.32 cm)
Temperament:Semi-aggressive
Temperature:72.0 to 86.0° F (22.2 to 30.0&deg C)
 

Habitat: Distribution / Background

The Jack Dempsey Rocio octofasciata (previously Cichlasoma octofasciatum) was described by Regan in 1903. This species is not listed on the IUCN Red List. They are found in North and Central America; Southern Mexico, Guatemala, Yucatan, and Honduras. Feral populations have been found in the USA, Australia, and Thailand as well. They inhabit bogs and other warm, slow moving, and swampy waters, living among weedy areas with sandy or muddy bottoms. They feed on worms, crustaceans, insects and fish.

The Electric Blue Jack Dempsey is a naturally occurring color-morph of the Jack Dempsey which has often been bred in captivity. It is said that for a long time hatched fry with this bluish coloration were consider runts and were discarded. This is no longer the case and in fact the fry which display the Electric Blue coloring usually sell for higher prices when mature. They are relatively easy to breed but take a lot of time and the right set-up, so they are more rare and costly than their parentage. Other common names are Blue Dempsey, Electric Blue Dempsey, and Jack Dempsey Neon Blue.

  • Scientific Name: Cichlasoma octofasciatum
  • Social Grouping: Groups
  • IUCN Red List: NE – Not Evaluated or not listed

Description

Just like its parentage, the body of the Electric Blue Jack Dempsey is stocky and compact. However this variety is a little smaller reaching closer to the 8 inches (20 cm) in length, rather than the almost 10 inches (25 cm) of a full size Jack Dempsey fish. They generally have a life span of 10 – 15 years.

This beautiful variant exhibits a coloration comprised of mostly ‘blues’ rather than the ‘greens’ seen on the normal Dempsey cichlid. They have a dark brown background contrasted with brilliant metallic and iridescent blue flecks. Males develop long pointed dorsal and anal fins and may also have a round black spot in the center of the body and at the base of the tail. Juveniles are less brilliant, having a white to light tan background with faint turquoise to blue flecks that get bolder with age.

If stressed or moody these fish can exhibit great color change in the aquarium, and also with age. Stressed fish will be lighter and their spots will be less striking.

  • Size of fish – inches: 8.0 inches (20.32 cm)
  • Lifespan: 15 years

Fish Keeping Difficulty

The Blue Dempsey is an easy fish to care for and a great Cichlid starter fish for beginners. They are not overly demanding when it comes to water conditions and will take a variety of commercially prepared foods.

  • Aquarium Hardiness: Very Hardy
  • Aquarist Experience Level: Beginner

Foods and Feeding

Since they are omnivorous, the Electric Blue Jack Dempsey will generally eat all kinds of live, fresh, and flake or pelleted foods. They get quite large so they should be fed a high quality pelleted food and large chunk foods such as meat or fish.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

TheElectric Blue Jack Dempsey is fairly easy to care for provided its water is kept clean. Aquariums are closed systems and regardless of size all need some maintenance. With home aquariums the nitrate and phosphates build up over time and the water hardness increases due to evaporation. Because these fish are very sensitive to pollutants and pH instabilty, it is important that at least 15- 20% of the tank water should be replaced bi-weekly, especially if the tank is densely stocked. When performing the water changes always use a gravel cleaner to make sure all of the decomposing organic matter that has built up is removed. The majority of of problems that occur with tropical fish tanks usually come down to one cause, decomposing organic matter.

  • Water Changes: Bi-weekly

Aquarium Setup

A minimum 40 gallon aquarium is suggested, though a larger tank would be suggested if keeping them in a semi-aggressive community tank with other like sized fish. They need good water movement along with strong and efficient filtration.

Although Dempsey’s can tolerate a fairly wide range of conditions, it has been suggested that warmer temperatures lead to more aggression in this fish. Many aquarists will keep the maximum aquarium temperature below 78° F (26° C) to help reduce antagonism.

Provide a bottom of fine sand and plenty of hiding places among rocks and wood. Plants are appreciated but should be hardy, such as Sagittaria. Place the plants around the inside perimeter leaving an open area in the center for swimming. The plants should be potted to protect the roots.

The Electric Blue Jack Dempsey is a rewarding specimen for the aquarist as it is moderately easy to keep as long as the aquarium is maintained.

  • Minimum Tank Size: 40 gal (151 L)
  • Substrate Type: Sand
  • Lighting Needs: Moderate – normal lighting
  • Temperature: 72.0 to 86.0° F (22.2 to 30.0&deg C)
  • Breeding Temperature: 86.0° F
  • Range ph: 6.5-7.0
  • Hardness Range: 8 – 12 dGH
  • Brackish: Sometimes
  • Water Movement: Moderate
  • Water Region: All

Social Behaviors

Though the aggressively territorial Jack Dempsey is not considered a good community fish due to their proclivity to defend their territory, the Electric Blue Jack Dempsey has demonstrated a much more tolerant attitude towards tankmates. That being said, as this fish ages it can tend to become more territorial and aggressive, especially when it is time for them to spawn. If they become too aggressive to cohabitat with the other members of the tank, it is recommended they be transfered to a species only tank. If keeping more than one, it is easier and safer for them to keep them in large groups rather than in pairs.

The author has successfully kept an adult Electric Blue Jack Dempsey with a 12″ Peacock Eel, a 10″ Chocolate Plecostomus, and a 4″ Upside-down Catfish for several years. They get along very well.

  • Temperament: Semi-aggressive
  • Compatible with:
    • Same species – conspecifics: Yes
    • Peaceful fish (): Threat
    • Semi-Aggressive (): Monitor
    • Aggressive (): Monitor
    • Large Semi-Aggressive (): Monitor
    • Large Aggressive, Predatory (): Monitor
    • Threat
    • Shrimps, Crabs, Snails: Threat – is aggressive
    • Plants: Threat

Sexual differences

The male has a longer and more pointed dorsal fin than the female. The male may also have a round black spot in the center of the body and at the base of the tail. The female has fewer spots than the male.

Breeding / Reproduction

The Electric Blue Jack Dempsey Cichlid has been bred in captivity. They are one of the easiest cichlids to get to spawn but as pairs they can become territorial, intolerant, and biters.

The Dempsey fish are egg layers. The female will lay 500-800 eggs on carefully cleaned rocks. They form a nuclear family. The fry are kept in pits and are guarded by both the male and female in the manner of “monogamous cichlid” breeders. See more about cichlid breeding in: Breeding Freshwater Fish: Cichlids.

  • Ease of Breeding: Easy

Fish Diseases

They are subject to infections as well as other diseases that ail all freshwater fish. One common problem is Ich. It can be treated with the elevation of the tank temperature to 86° F (30° C) for a few days since they can tolerate higher temperatures. They are prone to the same diseases as discus. Head and Lateral Line Erosion (HLLE), which was previously called “hole-in-the-head” disease. is common with poor water conditions. HLLE presents as cavities or pits on the head and face. It is believed this may be caused by a nutritional deficiency of one or more of: Vitamin C, Vitamin D, calcium, or phosphorus. In addition, it is thought to be caused by a poor diet or lack of variety, lack of partial water changes, or over filtration with chemical media such as activated carbon.

As with most fish the Blue Dempsey Cichlids are prone to skin flukes and other parasitic infestations (protozoa, worms, etc.), fungal infections, and bacterial infections. It is recommended to read up on the common tank diseases. Knowing the signs and catching and treating them early makes a huge difference. For information about freshwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.

Availability

The Electric Blue Jack Dempsey is occasionally available online and in fish stores. Almost all the Blue Dempseys for sale will be captive bred, which requires a significant amount of time and resources, so they are rather expensive.

Sources

 

Featured Image Credit: boban_nz, Shutterstock