The World Of Jack Dempsey Cichlids

Breeding Electric Blue Jack Dempseys

How To Breed Electric Blue JDs

I wish to thank Dr. Martin Brammah mbrammah@gmail.com  for allowing me to post this article he wrote. For more detailed information on the care and breeding of Electric Blue Jack Dempseys, go to his website at: http://bluejax.co.uk/default.aspx

  

Obtaining a Pair: 

Adults JDs select their mates via a process of chasing one another around the tank and lip-locking, both of which are tests of the strength and health of the potential mate.  In the aquarium it’s best to have pairs of equal size (within a couple of inches) because males tend to be larger and more aggressive and can therefore do serious damage to a female that is much smaller.

 

 

Typically with cichlids, breeders obtain pairs by starting with six to eight young fish and rearing them together.  Once these fish reach maturity, some fish will pair up and the remaining fish (if they are still alive!) can be rehomed.  

 This method is fairly guaranteed to provide you with a pair, however there are two problems specific to EBJDs…

 Problem 1: 

Although it has been achieved, the general consensus is that EBJD x EBJD spawns result in non-viable fry, or at best very fragile fry that require extra special care.

 

Problem 2: 

The procedure currently held as the best way to produce spawns of EBJDs requires pairing an EBJD with a normal JD, a process that is potentially fraught with difficulties.  These difficulties can however be overcome.

 

I list the most common format for breeding EBJDs below:

 

1)  One or more EBJDs are purchased with the aim of getting a male of breeding age.

 

2)  Once the breeder EBJD male has been identified, multiple normal female JDs are purchased and put into the same tank as this male.  These females MUST be smaller than the EBJD male, otherwise they are likely to cause him serious damage as a result of their higher aggression levels.

 

3)  With luck, the male EBJD pairs with one of the females and the rest can be rehomed.

 

4)  This pair is allowed to breed and some fry are reared with the hope of getting a female.

 

Now for some science: 

If we call the electric blue gene ‘b’ and the normal gene (which is dominant) ‘B’ then the male has the genotype ‘bb’ and the female has the genotype ‘BB’. 

 

If we put this into a Punnet square (below: male on the top row, female in the left left column) then the proportion of each offspring genotype can be seen to be 100% Bb.

 

	b	b
B	Bb	Bb
B	Bb	Bb

 

All the fry will be heterzygous for colouration (i.e. carrying one normal ‘B’ gene and one electric blue ‘b’ gene), meaning that they will look like normal JDs, but be carriers for the ‘b’ gene.

 

5)  To get EBJD fry, a female from this first spawn must be reared to breeding age and then mated to an EBJD male (preferably not her father to avoid inbreeding problems).

 

This will produce the following offspring proportions:

 

	b	b
B	Bb	Bb
b	bb	bb

 

So 50% of the fry will be Bb and look like normal JDs but carry the ‘b’ gene for electric blue; and 50% will be bb i.e. EBJDs!

 

6)  At this point the commercial breeders cull the Bb fry and raise the EBJD fry to sell at hugely marked up prices.  Whether or not you cull the heterozygous fry, it is important to separate them from the EBJD fry because the heterozygous fry are much more aggressive than their bb siblings and rapidly outcompete them for food, resulting in the EBJDs dying from a combination of stress and starvation.

Other combinations: 

If it is possible to get EBJD fry from a male EBJD and a female normal JD, then it should also be possible to get EBJD fry from a female EBJD mated to a male normal JD.  The biggest problem here is making sure that the male normal JD doesn’t kill the female EBJD as males are much more aggressive than females in both normal JDs and EBJDs; and normal JDs are much more aggressive than EBJDs.  I suppose the most important thing would be to ensure that any males placed in the tank with the female EBJD were quite a lot smaller, to minimise the effects of aggression.  Even so I would keep a very close eye on proceedings!

 

The Breeding Tank:
The larger the better.  If the male gets too rough, the female needs room to get away. Decorate the tank with at least one cave and plastic (or well protected) plants for cover.  Provide a flat rock and perhaps a large plant pot as egg-laying sites.  Dempseys will redecorate a tank to their liking once breeding is on the cards. 

 

The addition of floating plants can help to remove unwanted chemicals from the water and will also encourage the growth of infusoria (microscopic organisms which make a great first food for fry).  Once free swimming the fry can be left with the parents for a while and fed on newly hatched brine shrimp (although they may take the frozen version) or finely crushed flake.  Once the parents lose interest in their brood, the fry should be moved to rearing quarters for growing out.  Don’t raise more fry than you can reasonably rehome!   

 

— — —    written by: Dr. Martin Brammah    — — —