Another New-Age Cichlid Question

Question

My 125-gallon New Worl   QUESTION: Professor Coleman,

Firstly, Thank you very much for your always knowledgeable and helpful
responses to my questions.

I have fine-tuned my 125-gallon cichlid aquarium since we last spoke and I
have some more questions.

There is currently 1 oscar, 1 female green terror, 1 female dovii, 1 male green
pike, 1 male jack dempsey, and 1 male firemouth in the 125. I will be adding
my smaller fish to it once they grow a bit: 1 electric blue jack dempsey, 1 pair
of convicts, 1 male green severum, 1 female gold severum, and an ornate
bichir. I found a place near by that sells freshwater rays (Potamotrygon
leopoldi) - would it be possible for me to put one of these in my tank given
its company? Also, I have small/round gravel as substrate right now. Someone
told me that I should switch it all out for sand, is that necessary? The tank
has been well established since the first week of September 2008, I don't
know how I would go about changing the substrate at this point.

I have attacked a photo of my tank, any tips on decor/substrate/arrangment
etc. would be much appriciated!

Thanks for your time!

- Blake







ANSWER: Hi Blake,
 I would not switch the gravel.  

 That said, if you were to put a ray in there, you absolutely have to have a fine sand substrate for the ray to bury itself in.  But, I would not put a ray in your existing tank.  In my experience, cichlids tend to find rays incredibly interesting and constantly pick at them, and this can seriously harm the ray or even kill it.  

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>


---------- FOLLOW-UP ----------

QUESTION: Could you give me suggestions on breeding my Jack Dempsey cichlids? I am
quite confident that my electric blue is a female but the male is normal.
Could I end up with electric blue fry? It is X-linked dominant trait am I
correct? My convicts have tried to breed twice now, but the female won't let
the male anywhere near the eggs, I am not sure why this is? I was looking at
your research page for tips but I didn't see anything about getting Jack's to
breed.

Thanks,

Answer
Hi Blake,
  I have not actually bred Jack Dempseys, though I have bred dozens of other New World cichlids.  The key is almost always good water conditions. Give them a large flat piece of terra cotta, or a very large bottomless flowerpot, lying on its side and they should lay eggs on the inside.   

  The exact genetics of electric blue Jack Dempseys is a topic of a LOT of discussion and controversey.  I cannot say for sure.  One thing that is clear is that breeding two blues together doesn't work.  So, your pair may just work out.  Let me know what happens.   

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>