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Electric Blue Jack Dempsey Variation Emerges



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One of the oldest cichlids in the trade, the Jack Dempsey (Rocio octofasciata) got its name from the famous 1920s boxer, who, like this fish, was known for his aggressive nature and striking features. Within the past 10 years, another variation has emerged, the electric blue Jack Dempsey (EBJ).

The original variety, which was collected from the wild, came from Central America and quickly was bred by aquaculturists worldwide. The blue version has not been documented to occur naturally in the wild. There is great debate as to whether this fish has been hybridized or genetically altered through selective breeding. Some argue that this fish is simply a viable Jack Dempsey (R. octofasciata).

With the exception of color, the EBJ has similar exterior characteristics as the original variety. Unlike their wild cousins, however, EBJs do not grow as quickly or to the same maximum size. They also are not as territorial or predatory as the natural specimens. With a higher juvenile death rate, there is no doubt EBJs are more prone to diseases than their natural cousins.

So is it natural or not?

Hobbyists claim DNA studies have resulted in EBJs being proven a “real Dempsey.” Other reports indicate that such DNA studies are inconclusive. To date, there does not seem to be any scientifically reviewed study on the subject. Quite a few ichthyologists in South America are skeptical about their natural genomes. Upon observation, one might notice certain anatomical variances in the buccal cavity, cranial shape and dorso-ventral measurements.

Original breeders and exporters of EBJs explain that the blue gene is recessive, which is why we would never see them in the wild. It is a mutated gene, and the recessive inheritance is brought out through multiple generations. This might explain why the fish is “runt-ish” compared to natural Dempseys. It also would explain their slower growth, low juvenile survival rate and weakened immune response.

Many believe something was done to create this fish. The use of hormones to induce spawning or hybridization, or possibly non-natural egg/larvae rearing, has been speculated. Breeders of the first EBJs haven’t disclosed enough information to make a determination based on the data.

Patrick Donston, owner of Absolutely Fish in Clifton, N.J., is a regular contributor to petproductnews.com.
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