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El Acuarista®>Secciones>Blue Dempsey (Nandopsis octofasciatum azul) english version

Blue Jack Dempsey

Marcelo Casacuberta with photographs by the author

I remember my first acquaintance with the hottest novelty in the South American fish trade: the blue Jack Dempsey. It was at a small fish exhibition in Uruguay, and a young pair was shown in a 25-gallon tank.

My first impression was that they were misplaced among other freshwater tanks, since they seemed to be reef fish, so strong was their bright turquoise color. That was back in 1986, and since then this fish has occasionally been available, but always in limited numbers. No one seemed to know who was breeding them (although it was said that they came from Argentina), and the few people who tried to get a successful spawn from them (including myself) faced complete failure.

Even when the eggs hatched, the feeble fry were never able to swim, dying after a couple of days. The blue Jack Dempsey slowly acquired a legendary status, and speculations started to flow. Was it a new species, a mutation, or a sterile hybrid from two different species? The situation was much like what happens today with the blood red parrot. I had to wait more than a decade to meet Mr. Hector Luzardo, the man we could call the creator of this colorful morph, to find out the real story behind this unusual fish.

It all started in 1985 when Mr. Luzardo received a mated pair of young Cichlasoma octofasciatum as a gift from a friend. They had already spawned in the community aquarium where they lived, but the eggs disappeared in a few hours. It was a nice pair of young adult fish, but they were nothing to write home about. As soon as they were installed in their own tank, they produced a huge spawn of about 2,000 eggs, and the fry were removed to another tank after the eggs hatched. When the fry were about 20 days old, Mr. Luzardo removed a couple of young fish that were floating in the tank, their fins ripped and many scales torn.

Their color seemed to be paler than usual, but he thought it was due to the missing scales. The next day there were about four fish in the same condition, and still more the day after. Soon it was clear that this was more than just the weaker fry being attacked by the tougher ones. There were some fish in the tank that looked and behaved very strangely.

A closer look revealed about one-fourth of the fry gathering in one corner, looking smaller and thinner than the rest of their siblings. They were immediately transferred to another tank. After a couple of weeks the pale creamy color of the young fish slowly turned into a bright turquoise blue, growing into something completely different from their parents. A whole new type of fish had arisen.

Having bred them for over ten years, it is now clear that color is only one of the differences. The blue Dempsey's usually have a more elongated body, show more individual variations in the dot pattern, and lack the large lateral spot. They aren't always hungry, as are the standard kind, and they grow slower, although they reach the same adult size in the end. They are also mild-tempered, but only if you compare them to regular Jack Dempsey's. In fact, these fish are sometimes called the Pacific Dempsey by the local traders as a reference to their peaceful natures. In the local trade they have also been called blue Jack Dempsey's, although turquoise would be a more accurate word to describe their color. Baby blue Dempsey's are so lightly colored that it's hard to notice when they have white spot, a disease they are prone to catch during their first four weeks. They are easily cured if kept at 90°F (32°C) for three to five days. After their first month they become as strong and healthy as any other member of the genus, thriving in neutral, slightly hard water around 75°F (24°C).

In spite of the obvious differences from the rest of their siblings, young blue Dempsey's are not treated differently by their parents, who seem to recognize those pale fish as their own fry, treating them just like they do their ordinary fry. The reason nobody was able to breed the fish is that a pair of two blue Dempsey's will always produce sterile spawns or very weak wrigglers that will die within a couple of days. To succeed, Luzardo mates a blue fish with a common one that carries the "blue" genes. This way about 50 percent of the offspring are blue. If you have two common fish that carry the blue genes, only 25 percent of their descendants will turn blue. Care must be taken when pairing mixed couples, as the blue individuals can suffer from the rowdy behavior of members of the normal type. As strange as it may sound, this beautiful fish is barely known outside South America. They are only being bred by Mr. Luzardo, who has about 20 mated pairs, so it has always been available only in small numbers. A serious attempt to distribute this variety in North America and Europe has yet to be done.

Recently a shipment was sent to Germany to test the interest among the German hobbyists. I believe it is only a matter of time after introducing this outstanding animal to the cichlid fans before they become an excellent addition to their tanks. Soon they will become a sought-after item for all cichlidophiles worldwide.

Copyright © 2000 T.F.H.Publications Inc.
Reservados todos los derechos.
Revisado: 16 Dec 2011 01:36

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