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Is the EBJD the result of a hybrid cross?
 
Although this theory has been bandied around the internet for a long time, no-one has thus far been able to say exactly which species were involved in the production of the EBJD.  Nor has anyone admitted to making their own EBJD from hybrid crosses. 
 
It is a sad fact that much of the 'wisdom' concerning the origins of these fish is a whole bunch of conjecture and finger-pointing!
 
Previously I have been a little imprecise in my dealing of the hybrid theory and perhaps too quick to dismiss it.  In the interests of maintaining an open mind, I have rewritten this page for a third time!
 
Previously I menitoned that I had read on a forum that the EBJD was  a cross between Nandopsis octofasciatum (the 'normal' Jack Dempsey), Nandopsis tetracanthus (the Cuban cichlid), and Nandopsis haitiensis (the Black Nasty).  Apparently the mottled pattern comes from N. tetracanthus and the long fins come from N. haitiensis.
 
These photos show (from top to bottom) an EBJD, a Black Nasty and a Cuban cichlid:
 
 
 

Let's get something straight: I absolutely do not believe that Nandopsis haitiensis has anything to do with EBJDs, the fin shape is very different, as is the body shape, plus N. haitiensis regularly grow to over 12" - it just doesn't work. 

 

The case for EBJDs being the result of Jack Dempsey x Cuban cichlid are a little more compelling.  Certainly the mottling of the Cuban is quite similar to that of the EBJD.  However, in Cubans the degree of thick black mottling is concentrated on the head and gills, which is not the case in EBJDs.  Also adult Cubans have much squatter, chunky bodies, whereas EBJDs are much more elongated in shape.  Having said that, Jeff Rapps (www.tangledupincichlids.com) has informed us that it is incredibly unlikely that Hector Luzardo would have had access to N. tetracanthus in the early 80's.

 

Further support for this theory potentially comes from information supposedly provided by the guys who first discovered the EBJD claiming that it was a hybrid between the Jack Dempsey and the Jaguar cichlid "Cichlasoma" managuense.  As the Cuban cichlid is quite similar to the Jaguar cichlid in appearance, it is possible that the company has wrongly identified the fish that they were hybridising.  However, it seems unlikely that a business that makes its money from selling fish would make such a mistake!

 

A mitochondrial DNA test was done to test the similarity of mitochondrial DNA between normal Jack Dempseys and EBJDs.  The test found the DNA to be identical.  This has been misread by some to represent proof that EBJDs are not hybrids.  However, mitochondrial DNA is inherited from a fish's mother and not father, so while we know that EBJDs are 100% related to the maternal lineage of Nandopsis octofasciatum we remain uncertain about the paternal lineage (i.e. the exact genetic make-up of the father).  This leaves us back at square one.

 

The two other nuclear DNA tests that have been carried out have also been inconclusive, despite supporting the hypothesis that the EBJD is a colour morph.  The problem with these tests are numerous.  Firstly, the fact that EBJDs have been back-crossed to wild JDs for the last 20 plus years, means that even if the EBJD is a hybrid, the majority of its genome is likely to be JD in origin now, as a result of the dilution effect resultiong from all these back-crosses.  Secondly, nuclear DNA tests only look at a tiny proportion of the whole genome of each fish tested.  As such, the chances of finding the exact nucleotide sequence that controls blue colouration in EBJDs are much like the chances of finding a needle in a haystack!

 

Sadly the best way to show that the EBJD is not a hybrid would be to show that all its genetic make-up is JD in origin and that no part of it comes from another species.  The time and money such an endeavour would require is currently excessive, given the 'value' of this fish in a commercial sense.

 

The bottom line: on the EBJD Forum we deal with facts.  So far all the factual evidence we have appears to point to the EBJD being a colour morph.  However, pretty much every day I read something that makes me stop and think that maybe they are hybrids after all.  You have no idea how incredibly frustrating that is!