Jack Dempsey Fish: How To Care For This Feisty Cichlid

If you’re looking for a docile, dainty fish for your tank, you’d probably be disappointed with the Jack Dempsey fish.

However, that hasn’t stopped them from becoming one of the most popular aquarium cichlids.

In this guide, you’ll learn all about Jack Dempsey cichlids and how to care for them. These freshwater fish can be incredibly rewarding to keep, and by the time you’re done reading this, you’ll know if they’re right for you.

Species Summary

One of the most popular tropical aquarium cichlids, the Jack Dempsey is named for its similarity, both in facial appearance and aggressive behavior, to the legendary boxer.

A member of the Cichlidae family, which also includes angelfish and discus, the Jack Dempsey fish, or Rocio octofasciata, is native to Central America in places like Mexico, Belize, Guatemala, and Honduras. 

In addition to their native habitats, Jack Dempseys have been found in Australia, Thailand and even the United States, including Florida, South Dakota, Connecticut and Hawaii. The wanderers most likely escaped from fish farms or were released by aquarists who either couldn’t, or didn’t want to, care for them.

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Its ability to survive warm, even hot, water temperatures up to 86 degrees further proves the Jack’s hardiness and the appropriateness of its name.

Appearance And Size

As its name suggests, the Jack Dempsey cichlid exhibits the large facial features and aggressive behavior of the famous boxer.

Although both sexes feature long fins and large oval, muscular bodies ranging in size from 10 to 15 inches, the more brightly-colored males sport longer bodies and even longer fins with pointed tips. The fish’s thin body shape is characteristic of cichlids and other species of carnivorous, predatory fish.

Jack Dempsey Fish at bottom of tank

One reason Jack Dempseys are so popular is that they come in a wide range of pretty colors. The most sought after and attractive coloration of the bunch tend to be shades of:

  • Gold
  • Pink
  • Blue

Young fish begin life as pale gray or tan flecked with green and between 10 and 12 distinctive vertical stripes.

As the fish ages, the stripes fade, although traces of iridescent blue, green and turquoise scales remain on a deep blue background. The fish’s operculum, or gill cover, features the same beautiful patterns.

The Jack’s lighter blue lips provide a striking contrast, giving the appearance that the fish is wearing pale frosted lipstick! The red tips on the dorsal fins are another eye-appealing contrast.

The Electric Blue Jack Dempsey

If you prefer a less aggressive fish than the standard Jack, the smaller Electric Blue Jack Dempsey features an iridescent pale blue color and longer fins.

The Electric Blue Jack Dempsey

However, as often occurs with hybrids, there are individuals that display various skull shapes among siblings, and some may feature irregular scales. The Electric Blue is also more expensive than regular Jacks.

There’s disagreement as to the Electric Blue’s origin. Some argue it’s a cross between a standard Jack and another species of cichlid, while others believe it’s the result of a mutation.

General Care Guidelines

Jack Dempsey cichlids generally require a simple care regimen when it comes to their health, especially if you don’t keep a large group in one tank or combine them with other fish species. Because handling their aggression can be a challenge, you should only consider keeping Jack Dempseys if you’re a relatively experienced aquarist.

With proper care, Jack Dempseys can live from eight to ten years. Water quality can influence this significantly, so keep your tank clean to prevent disease-causing organisms from breeding. Always quarantine new animals, plants, and rocks before you add them to your aquarium.

Also take care not to overfeed them, as not only will too much food cause obesity, but leftovers can contaminate your tank. This is a common mistake that many new owners make, but it’s easily corrected.

Common Illnesses

Even with the best of care, Jack Dempsey Fish can become ill like any other animal. A common health issue, Ich, or white spot disease, shows up as white nodes on the fins and general body surface. To treat fish affected by this ectoparasite, raise the water temperature in your tank to 86 degrees.

Poor nutrition can lead to head and lateral line erosion, or HLLE, a common disease that produces pits or cavities on the fish’s head. Changing to a proper diet should alleviate the symptoms of HLLE.

When setting up your tank for Jack Dempseys, you want to make sure the conditions are as close as possible to their native habitat. Remember their wild cousins live in slow-moving, tropical waters, such as canals, lakes, murky rivers and swamps.

The minimum tank size should be 55 gallons to satisfy each fish’s territorial instinct. Two or three adults would be happy with a tank that holds from 55 to 150 gallons.

A heater is essential to maintain a water temperature between 72 and 86 degrees. Keep a thermometer in the tank to ensure the temperature remains within this range.

Jack Dempseys prefer a somewhat acidic environment, so keep the pH from around 6 to 8.

In terms of water hardness, shoot for a range of 9-20 dGH.

Two chemicals that must never be present in your tank are ammonia and nitrate, which even in small amounts can cause stress in your fish. If fish are exposed to these pollutants over a long period of time, their immune systems will weaken and make them more susceptible to disease.

Because the Jack’s natural habitat is slow-moving water, you don’t need an air or water pump in your tank. A filter is all you need to provide them with the slight current of their native habitat.

Jack Dempseys are large fish and produce lots of waste, so you’ll need a powerful filter to keep the water clean. Either a canister filter (like the FX4) or a good-sized hang-on-back, or HOB, power filter is a smart choice. Don’t be afraid to select a filter that’s a size larger than recommended because it needs to handle a large tank that holds large fish.

The Ideal Lighting Setup

When lighting your tank, you want it to mimic the natural appearance of deep water. Although fluorescent lighting is most popular for aquariums, it tends to highlight only the substrate, plastic plants, and ornaments while losing the natural colors of the fish themselves.

Also over time, fluorescent bulbs dim and need to be replaced within months in order to retain the quality of lighting.

Gaining in popularity, LED lighting consumes much less energy and lasts for years. In addition, LED lighting creates a more natural-looking tank. If you think your fish would like some shade, try adding a floating plant, such as hornwort.

Additional Habitat Recommendations

Because they like to hang around in the lower or middle levels of the water, choose a sandy substrate, such as gravel, grit or a mix, about 2 inches deep for the floor of the tank. Jack Dempseys are typical cichlids that dig in the substrate for food, so fine sand is the best choice, as it’s the easiest for them to sift through and hunt. 

Another advantage of sand is that it settles and levels itself after the fish dig in and sift through it. Larger gravel, in contrast, forms uneven piles and craters when disturbed.

Place several caves throughout the tank so each fish can claim its own territory. Driftwood logs, branches, plastic plants, and rocks provide them with a safe hiding place. Vallisneria, or eelgrass, gives the fish a tall, underwater meadow-type environment to swim through. You can also add tough live plants, such as Anubias or Java moss.

Jack Dempsey Fish Food & Diet

In the wild, the carnivorous Jack Dempsey will consume any animal that fits in its mouth, including small fish, worms, insects and crustaceans. Because they aren’t fussy, you can feed them prepared, frozen, fresh or live food.

Processed dried foods, including pellets and flakes, are inexpensive and widely available. No matter whether the pellets float or sink, Jack Dempseys will eagerly devour them.

If you feed them prepared foods, you should occasionally offer frozen or live foods to ensure your fish get all the nutrients they need.

You can also feed them exclusively fresh or live foods. Some delicacies that they will enjoy are:

  • Bloodworms
  • Fresh or frozen shrimp
  • Fruit flies
  • Brine shrimp
  • Crickets
  • Grasshoppers

Feed adult Jack Dempseys one or two times daily, but feed young fish two or three times a day to ensure they get the nutrition they need to grow. Feed only what your fish can eat within a couple of minutes, as any leftovers will decay and contaminate the water.

Behavior & Temperament

You’d expect any animal named after a legendary boxer to display an aggressive behavior, and the Jack Dempsey cichlid is no exception. Because of its temperament, this typical cichlid does best when under the care of an experienced aquarist.

Just remember males are territorial, so it’s important to provide enough caves and crevices for each fish to establish its own territory for hiding.

Jack Dempsey Fish Tank Mates: Good And Bad

Because of the Jack Dempsey’s nature, you will want to consider their tank mates very carefully. The safest option is for you to keep them as the sole species in a tank, especially if you’re not experienced in handling their aggression. It’s also best to have only one male per tank to avoid aggressive territorial behavior.

Unless you want them to end up as a meal, don’t place peaceful fish, such as tetras, or invertebrates, such as freshwater snails and shrimp, in the same tank as Jack Dempseys.

Species you might consider as good Jack Dempsey tank mates are those of a similar size with the ability and temperament to stand up for themselves. Some popular choices are:

  • Firemouth Cichlids
  • Blue Acara
  • Angelfish
  • Plecos
  • Clown loaches
  • Silver Dollars
  • Convict Cichlids

Breeding Advice

To prevent inbreeding, purchase your fish from different breeders at different times. Jack Dempseys are relatively easy to breed and do best when you raise four or five together and wait for one pair to leave the group.

One thing to look out for is the possibility that the pair will try to bully and scare away the other fish. This may necessitate your removing the remaining fish from the tank before they’re killed.

Pay attention to the color of your fish when attempting breeding. This will give you a good indication of the timeline and when they are ready to mate. When they are, Jack Dempseys will darken in color, turning nearly black.

If the female isn’t yet ready to breed, the male may try to chase and harass her. You may need to remove her from the tank until she’s ready to spawn; and when you think she is, try to introduce her to the male again. If all goes well, the pair should end up as mates for the rest of their lives.

A flat stone is a good place for Jacks to spawn. You’ll see the pair first inspect and then clean the stone to prepare it for spawning. When she’s ready, the female will lay her eggs on the stone, up to 500 at a time. Once this is done the male will fertilize them.

This part of the process is very interesting to watch even if you’ve bred other species of fish. We’re fans of the rock cleaning process (it’s very cute).

After about three days, the eggs will hatch. The parents will then collect the fry and place them into pits they’ve dug in the substrate to hide them from intruders. In about 10 days, the fry will be happily swimming about!

Are They Right For You?

Jack Dempsey fish are popular for a reason, but that doesn’t mean they’re for everyone.

If you’re someone who doesn’t want to deal with aggressive fish and prefers a mellow tank vibe, then these creatures aren’t for you.

However, if that doesn’t turn you away and you really like the look of the fish we highly recommend getting one. Caring for and keeping Jack Dempseys can be a very rewarding experience!

We hope that this care guide was helpful and has given you the essential information you need. If you have any follow up questions or suggestions on how we can make our guide better, let us know!

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