Jack Dempsey Fish: New Kid on the Block!

Reviewed By Tom •  Updated: 09/27/21 •  6 min read
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Jack Dempsey Fish

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The popularity of cichlid fish dates all the way back to the 1940s. Originating in South America, numerous different kinds of cichlid fish are kept as pets because they add a lot to an aquarium on a visual level.

They are always energetic and colorful, with each different specific cichlid species having its own distinct and vibrant pattern. They’re also pretty rare in the wild which makes them that much more exciting to have at home. 

The Jack Dempsey fish is a variety of cichlid that has been around since they first broke onto the scene, but has recently started to a pretty big jump in the amount of people who include them in their aquariums.

You can probably get a bit of a sense of what kind of fish this is from the name. Jack Dempsey was a massively popular and successful boxer, who was at the height of his fame all the way back in the 1920’s.

Now this doesn’t necessarily mean that a Jack Dempsey fish is going to start fighting every other fish you’ve got in your aquarium, but what it does mean is that they are tough and hardy little guys who will be able to defend themselves.

And so you’ll need to make sure that if you do decide to invest in a Jack Dempsey fish, that the others present in your aquarium are just as tough and hardy. So let’s learn a bit more about these guys, shall we?


Initially, Jack Dempsey fish are likely to be quite skittish, and could even be somewhat shy when you first introduce them to the tank. Don’t be surprised to see them retreat behind a plant or an ornament and spend most of their time there for the first couple of days.

And you should be prepared for that. You should always make it a priority to include hiding places in a fish tank anyway. Plants, rocks, driftwood, numerous different kinds of ornaments and even plant pots and piping all make for great hiding places.

Don’t be fooled by this initial behavior though. Once they get acclimated to the tank, they will start to try and assert their dominance. You’ll often see them trying to single out a smaller fish that they can pick on.

You can prevent this by having quite a few different fish in there, which will make it too crowded for them to easily work on one fish. If all of them are roughly the same size and similar in temperament, you should be able to offset the aggression.

In line with that, Jack Dempsey fish are also quite territorial and you could see them fighting other fish in the tank that infringe on their space. This makes the hiding places all the more important. Every fish can have its own territory.


Taking care of these fish is actually pretty straightforward and that’s probably another part of the reason why they are so popular. They are not among the more disease-prone fish out there and they can live for up to fifteen years. 

They do of course have certain needs, as all fish do and you will need to make sure that the others present in the tank can live in the same environment. You need to think about filtration. Fish dispel a ton of waste which will result in ammonia in the tank.

This is basically poison for the fish and so it will require constant filtration. These are big fish and because you will have a tank full of big fish I would suggest getting a rather large filter. You will need to change the water maybe once a week too.

Take out half of it and replenish it with clean water, which you then have to treat with a conditioner to neutralize the toxins in tap water. You can get these in any pet store. Because these are tropical fish, you will also need a heater.

I would suggest a big and sturdy one of those two. It will be a bit more expensive, but you’ll need it for the size of the tank and the better the heater, the longer it will last so it will be a solid investment.

And as we mentioned earlier, there’s not a lot of diseases that Jack Dempsey fish are likely to be afflicted by, but one you should watch out for is ich. This will be obvious because it will cause white spots on the body and you will need to get a specific kind of medication for it. 


As you can probably imagine, Jack Dempsey fish are predators and they are naturally inclined towards hunting down and eating other fish. This means that they will need to have a diet that’s high in animal protein.

So in addition to some top-quality pelleted food, you should also feed them some live food such as black worms, daphnia and brine shrimp. Maybe a couple of times per week for the live food and the pellets every single day.

For fish that are still growing, you want to be feeding them maybe 3 times per day and you can reduce that to just 1 or 2 once they have reached full maturity. And like all fish, you should also include some vegetables in their diet

Peas are ideal because they are small and easy to swallow, but you could also feed them little bits of chopped up carrot or cucumber. Once again, every couple of days for this, maybe alternate days with the live food and the vegetables. 

Though they are beautiful fish to look at, Jack Dempseys might not be for everyone. The aggression does put some people off and you do need a huge tank because they get very big. But if that kind of fish sounds like it’s up your alley, then a Jack Dempsey fish will be an excellent choice which you can take care of without too much hassle.

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Tom has always loved to write since he was little - he wanted to be either a writer or a veterinary doctor, but he ended up being a professional writer while most of his works are based on animals. He was born in San Francisco but later moved to Texas to continue his job as a writer. He graduated from the University of San Francisco where he studied biotechnology. He is happily married and a soon to be father!

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