I wouldn't keep them in a 10 gallon and I wouldn't cycle a tank with them. They are fragile fish that often die for no apparent reason, I've tried them twice and gave up.
I am thinking in getting some Jack Dempseys for my new 75 gallon. From what I have read, the blue ones max out at about 4 inches I think, and they do like pretty specific water perimiters and I wouldn't reccoment putting them into 10 gallon or even cycling with them. If you were going to use fish to cycle, you should cycle at first with out the fish, then do a large water change and add a few feeder fish. As long as your ammonia isn't really high, the feeders should be fine (i think). Im sure someone else who knows more than I do will respond to this also.
P.S.
I am hoping to breed JD's in my new 75 gallon and I know that to get the Blue Dempseys, you need to mate a Blue one with a normal one. Has anyone tryed this? If so, could you give me some details.
I hear it's a recessive gene. They have to be mated back to normal Nandopsis octofasciatus "Jack Dempseys" each generation, and only a percentage of the fry turn out to have this coloration. "Blue Dempseys" mated together spawn, but the eggs fail to hatch. (There's a cool photo and some info at Age of Aquariums: www.aquahobby.com/dempsey.html
Has anyone personally seen a spawning that hatched?
I sure would like to read some solid material on these. I know that Jeff Rapps of TangledUpInCichlids in New Jersey is the sole distributor from the original breeder. And that the originator is a dark secret-- I heard that they were "native to Paraguay" a while back. Yah! and the pirated "Lord of the Rings" DVD too... smoke-blowing!
Well, a little more work with beloved www.google.com opens up a whole new world. The originator is fishbreeder Hector Luzardo of Buenos Aires-- and check out this photo of Blue Dempsey juveniles! http://luzardo.elacuarista.com/ You can read the Tropical Fish Hobbyist article in 2000 that set the Pacific Blue's on the map (it's in English) at http://www.elacuarista.com/secciones/tfhblue.htm That website has more detailed history of the "Pacific Blue" as the originator likes to call them, since the first fry turned up in his tanks in 1985.
