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Do You Know Jack?

Jack Dempsey cichlid

This week, we adopted a new fish for our aquarium: a half-grown Jack Dempsey cichlid (pronounced “sick-lid”). This 6-inch bruiser was previously in a larger tank where he was harassing an assortment of goldfish and koi. Now he has a tank all to himself, where he won’t have to share the space with any other fish.

While this may seem mean to some, this is actually typical behavior for Jack Dempseys and most other fish in the cichlid family. These fish are territorial by nature, and will actively defend their living space against all other fish. In fact, that is how this particular species got its common label; it is named after the famous 1920’s boxer William “Jack” Dempsey, because of its notable aggression and tenacity. Some even say the fish bears a strong likeness to the boxer’s defined facial features!

William "Jack" Dempsey the boxer

However, despite their reputation for ferocity, Jack Dempseys and most other cichlids are among the best parents on the fish world. A male and female will form a strong bond, and may remain together for several years. Cichlids are among the few groups of fish that form nuclear families; i.e. a monogamous pair with offspring. One reason they make such great moms and dads is that they will aggressively defend their young just as fervently as they defend their territory.

Jack Dempseys hail from Central & South American waterways, preferring slow-moving water & bogs. They like warm water in the mid-70s and a pH between 6.0-7.5, although if acclimated slowly, they adapt well enough to most water parameters. They are among the larger members of the cichlid family, averaging around 10 to 12 inches in length. Jacks are predatory by nature, eating virtually any critters they can gulp into their sizable jaws, including smaller fish, crustaceans, worms, and other invertebrates.

In addition to their tenacious personality, many aquarists are drawn to Jack Dempseys because of their vibrant green and blue coloration, especially in mature specimens. The emerald scalation of a grown Jack glimmers in a clean aquarium like a living jewel.

Overall, if you have a large, aquarium with plenty of filtration, and you are looking for a sizable, predatory fish with some nice color and a lot of personality, the Jack Dempsey cichlid would be a great candidate.
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2 Responses to “ “Do You Know Jack?”

  1. Sergei says:

    This tank is really cool! I’m sitnetg up a 100 gallon tank at the moment and am aiming to get some clown loaches and I was thinking about doing a cool little rock approach as you have done. Did you find this difficult to achieve and do you believe it’s a good way to decorate and utilise your tank? If I was a fish, I’d definitely have a lot of fun in here haha.

    • FinsNScales says:

      Hey Sergei,

      For this tank (which is a little small – only 27 gallons), I just picked up a nice-looking artificial stump decoration from the pet store. However, I am a big fan for naturalistic aqua-scaping, especially for larger tanks. I don’t know where you’re located at, but I don’t think it should very difficult for you to acquire some natural rock work for your aquarium. Most fish supply pet stores offer bulk rock by the pound in many varieties, but if you wanted to save a little money, you can easily check out a local rock quarry and see what they have. Might even find something you like in nature! Just make sure you don’t take anything illegal (from a construction site, or a state park, etc.).

      Once you get your rock, be sure to clean it off really well. Some hobbyists rinse it in a hot, bleach water solution, while others actually bake it in the oven to eliminate any harmful bacteria (all depends on where you got the rock from, I suppose). One other thing to keep in mind is that natural rock can raise your pH levels to some degree. Depending on the types of fish you plan on keeping, this can be good or bad!

      Clown Loaches, in my experience, seem to be pretty adaptable in a variety of conditions, so you should be good there. My only suggestion is to get a decent group of them: they love to school! Hope this helps and thanks for reading!

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