Zebrafish Breeding

Question
I am interested in breeding Zebra Danio.  I have done some research online about different ways to go about it.  My problem is that every method I have tried has resulted in dead adult fish and no babies.  What is a simple and fool proof method to breed Zebra Danio?  The latest method that I tried was a small 5.5 gallon tank filled about 1/3 full, with marbles covering the bottom.  I also included an air stone and a small submersible heater that was preset to 78 degrees F plus minus 2 degrees.  I tested the water following the last breeding attempt.  The only test out of the ordinary was a slightly elevated NH3 level, a little under 1 ppm.  For that breeding attempt, I had placed 5 males and 5 females in the tank because I had read that Zebrafish breed in groups and that more fish will cause a breeding "frenzy." What could be resulting in the fishes' death?  This has happened three times. The fish are kept in a larger 50 gallon tank before I put them in the separate breeding tank.  I don't use tap water in either tank.

Answer
Hi Ryan,
 I have bred them pretty much exactly the way you describe, except that I used a 10 gallon tank
and it was completely full of water.  I don't understand why you would only fill it a little.

-- Ron C.
  rcoleman@cichlidresearch.com
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