Jack Dempsey Fish Care: Tank Mates, Diet, Size, And More!

Jack Dempseys, more commonly referred to as Rocio octofasciata, are a tropical climate fish found in murky waters. Named after the famed American World Heavyweight Champion boxer, these fish belong to the cichlid order. Specifically, the South American Cichlid. As such, Jack Dempseys typically stay in waters of a temperature of 72-86 °F (22-30 °C).

By having a lengthy lifespan, these cichlids make great fish to keep in an aquarium. If properly maintained and cared for, Jack Dempseys can live for up to eight to 10 years. In the healthiest of environments, some have even made it to 15!

jack dempseys fish care guide

Typical Behavior

Like their namesake, Jack Dempseys have strong facial features and a rather aggressive demeanor. When they are under stress, their colors will change dramatically. Cichlids do better when provided with plenty of space and compatible fish with which to swim. These types like to burrow, so make sure that their tank has a lot of fine, deep sand.

Any form of decoration will do that allows your Jack Dempseys to hide, as they will often do. They also prefer direct light blocked from coming in. To accommodate this, place a blanket of live plants to sit on top of the water.

Since Jack Dempseys like to eat plant-life, be mindful of which genus you choose. Sagittaria is a great species that seems to well serve this purpose. It’s a horizontal creeper that is rather tough and hardy, helping to prevent it from being eaten and destroyed.

Keep in mind, though, that this can change overnight depending on their mood. They may like it at first. But should they change their mind, they may deliberately destroy it.

Appearance and Size

Their appearance somewhat resembles a speckled egg. When born, they start out as a light gray or tan color with turquoise flecks. Once they have matured, this coloration changes to a darker purple or gray. Much brighter flecks will be prevalent, too. These can be blue, gold, or green. Reaching their true coloration and design can take well over a year.

Discerning between sexes is simple. Male Jack Dempseys usually have a lot more spots than their female counterparts. Also different in males are bright red edgings along their fins. Some males will also develop a black round spot at either the middle of their body or the base of the tail.

Females can likewise get these spots, albeit smaller and in different locations. These are typically found on their dorsal fin and gill cover. Both of these cichlids can grow to a size of anywhere between 10 and 15 inches in total length.

Their bodies are more oval-shaped with pointy fins. Since becoming aquarium-kept fish in recent years, different color variations have been captive-bred. The most famous and sought after is the brilliant Electric Blue Jack Dempsey. Standard breeds will usually cost around five to 10 bucks. But an Electric Blue can be closer to $20.

Tank and Water Conditions

Jack Dempseys are native to Central America, Guatemala, Honduras, North America, and Yucatan. They live is boggy waters that are warm and swampy. They gravitate to areas that have lots of weeds, along with sandy or muddy floors. You will want to emulate their natural setting as closely as you can.

Begin with at least a 55-gallon tropical freshwater tank. This will accommodate one Jack Dempsey. If you plan on keeping more fish, an increase in tank size is a must. Ensure that their water moves decently, but not too rapidly. A filter will serve this purpose nicely. Since Jack Dempseys like slow-moving waters, you won’t need any pumps.

Floating plants are recommended; just make sure that it adequately blocks light. A moderate to normal lighting level works the best. At the same time, you’ll need to leave plenty of room for your fish to swim. Due to the water becoming murky from their burrowing habits, prime filtration is a must. Jack Dempseys don’t like a lot of direct light, so the more coverage, the better.

Also to that point, any plant-life that you put in the tank will need to be in pots, elsewise the fish may dig them up. Plenty of fine sand and rocks will serve to help with both of these factors. Also important is the water’s pH level, which needs to be between 6.5 to 7.0.

Jack Dempseys live among temperatures as high as 86 °F in the wild. But they have shown more aggressive behavior in warmer waters. Most owners find that maintaining a temperature of 78 °F will keep their cichlids calmer. This is tantamount when living among other fish.

Keep any decorations resting on the bottom spread evenly apart. Jack Dempseys are quick to claim territories. If you are going to keep them in groups, ensure that you have plenty of crevices for each one to inhabit. Any kind of sunken ship, castle, or log will do as long as there are several holes for your fish to hide inside.

Food & Diet

In the wild, Jack Dempseys live on a diet of worms, insects, shrimp, and even other fish. In your home, however, any kind of flake or pellet food should do the job. Be sure to add in some live meaty foods, too. But steer clear of beef and poultry, as this type of meat can be harmful to your cichlid. They will also try to eat any live plants that you may choose to put into the tank.

To alleviate this tendency, toss in some cucumber and lettuce from time to time. It’s certainly fine to feed them their preferred staple of worms and shrimp, but only partially. These fish feed often, so you’ll need to provide flakes and pellets several times a day.

Jack Dempsey Fish Tank Mates

While the Jack Dempsey fish is low maintenance and easy to care for, they don’t play well with others. They tend to become territorial as they grow. You’ll find that it’s easier to keep them with other fish while they’re young. But their behavior will change as they mature.

When kept with other Jack Dempseys and cichlids, they run the risk of getting bitten or eaten in their later stages. You may keep them together at first. but you’ll want to move them to their own tank later on. This will avoid such aggressive and problematic behavior.

If you wish to keep more than one Jack Dempsey, do so in large groups; never keep them in pairs. Shrimps, snails, and even crabs run the risk of harm, so be sure to separate them if you keep these kinds together during the cichlid’s youth.

Breeding

Jack Dempseys are one of the easiest in their order to get to procreate. But again, if kept in pairs they can even eat their own spawn if their mood changes. This can result from a simple change in their habitat and surrounding. It is vital that you keep close watch of their temperament after breeding and the laying of eggs.

You’ll need to ensure that you provide a hard and flat surface somewhere in the tank on which they can lay their eggs. If you don’t have a flat rock or log, a cleared area on the tank’s bottom glass will do just fine.

As long as your Jack Dempseys’ environment stays normal, you will find them to be very attentive parents. They are also very protective. Both parents like to sit on their eggs for incubation and to guard them.

The female will lay some 500 to 800 eggs. Once hatched, the parental Jack Dempseys will feed their fry as a mother bird does with her young. They will first chew up the food and then release it into the young’s mouth for consumption.

Breeding Jack Dempsey fish is moderately difficult. This stems from their well-documented aggression toward one another. It’s a must that you to keep a close eye on their progress. You’ll need to move them around accordingly.  This will avoid infighting or the potential eating of their fry or one another.

Jack Dempsey Fish Care Guide

It’s vital that you clean your Jack Dempseys’ environment bi-weekly. Water needs added this often to counter the problems caused by natural evaporation. You will generally be replacing 15 to 20% of your tank’s water volume.

Jack Dempseys are very sensitive to incorrect pH levels. Other pollutants can develop when the water gets too hard from evaporation. Any time you’re dealing with tropical fish and their tanks, removing waste is going to be of prime importance. Using a gravel cleaner will help exponentially during the cleaning process.

Once you have moved an aggressive Jack Dempsey to another fish tank, be sure to give your single fish the same level of care that you would give to a group. If you wish to keep many Jack Dempseys but have only one tank, consider going with the Electric Blue variation. They are a smaller, less hostile, and all-around friendlier fish when compared to standard Jack Dempseys.

As with any freshwater fish, Jack Dempseys are prone to infections and other water-borne diseases. Viral, bacterial, and fungal diseases like furunculosis – a deadly serious septicemic plague that is highly contagious – are all known potential dangers to your fish.

Bacterial kidney disease, coldwater disease, vibriosis, and enteric redmouth disease are all concerns that you’ll need to monitor. Jack Dempseys are also able to acquire parasites like worms and protozoa.

Moreover, Head and Lateral Line Erosion (HLLE) is another common disease that is the result of poor tank maintenance. A lack of proper feeding can result in HLLE, as well. Commonly referred to as “hole-in-the-head disease”, this occurs when fish aren’t receiving the proper vitamins.

Providing plenty of essential Vitamin C and Vitamin D, phosphorous, and calcium will help to prevent this awful condition in your fish. It is vital that you research and familiarize yourself with these diseases and conditions. Then you will know exactly what to look for in the event that your fish is susceptible to them.

Proper tank maintenance and precautionary measures go a long way. This will assure that your fish and other aquatic creatures live a long and healthy life while in your care.

Are They Right For You?

The Jack Dempsey fish’s stunning color array makes it a top selection for aquarium owners. They are easy to find in pet stores and are highly affordable fish. They have personalities that lend to some spectacular observations.

Before you commit to Jack Dempseys you need to be sure that you have the capacity to keep them. Each fish needs at least 55 gallons of water. If you’re going to be keeping a group of them, you’ll need a minimum of 80 gallons. As fish that like to stay busy, you can expect a lot of activity in your tank. They are a blast to watch burrow into the sand or hide inside of cave-like decorations.

They are a rather moody fish, which serves to make them moderately difficult in their care. Be prepared to give them a lot of attention throughout their beginning stages of life should you decide to breed them. They will require a lot of moving around initially. But once they get settled into their permanent home, your Jack Dempseys can enjoy a long and comfortable life.

Color varies wildly among their species. Since they are prone to changing, you can’t expect your new purchase to remain in its current state. As it matures, its color scheme will likely look vastly different from its initial look.

Their colors are astonishing to watch change over time. And being temperamental, you may even observe them changing color later in their adulthood. Once you get the hang of how they need attended to, Jack Dempseys will provide your aquarium with thriving splendor.

Richard Rowlands
Richard Rowlands

Hello fellow aquatics enthusiasts! My name is Richard Rowlands. I’m an aquarium keeper and enthusiast and have been for about 25 years or so. While I won’t claim to be the end-all expert on aquatic life, I will say that I know my way around a tank.

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