PROBLEM: Many people go to the pet store and just start picking out fish for their new tank like an interior decorator picks out new furniture for a mansion. Often the only criteria is what looks good; i.e. the most colorful fish or the most impressive. Occasionally, their checkbook makes the decisions and only the cheap fish are selected. While there is nothing wrong with desiring the nicest-looking fish for your aquarium, or simply being economical, there is often very little thought given to the long term “big picture.” Can your tank really hold that many fish? Will that fish outgrow the aquarium? Stocking the aquarium with either too many fish or fish that are too large can result in several issues, and can end up cost you more money in “repairs.”

ISSUES: Can you imagine sharing a house with 20 other people? What if that house only had one bathroom? Remember that no matter the size, an aquarium is still a closed system and can only handle so many occupants. If the system is overloaded, it cannot effectively provide a healthy environment for all the creatures living inside.

Not all fish are “community” species; i.e. many fish are territorial or even predatory. Mixing any ole’ kind of fish is not recommended without researching that fishes’ habits. Likewise, most fish sold in pet stores are young specimens, and several species can grow quite large, including common goldfish, the “algae-eater” Plecostomas catfish and personable predators such as Oscars. Some of these will routinely grow over 12 inches in length!

SOLUTION:Take care to evaluate your tank size, and research the eventual adult size & behaviors of the fish you wish to keep before stocking the aquarium. In the long run, this will save you money and grief, as well as resulting in a healthy aquarium both you and the fish that live within it will enjoy.

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!

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.