Originally Posted by Ericwm
There is an article on these fish in a resent issue of coral magazine. There is a free subscription for the iPhone/pad, I would recommend giving it a read. They do not release fry, they hold them in the dads mouth until they hatch and skip the fry stage. Little fish hatch and there is no need for an urchin, they are just for protection. There are people that make fake urchins for them with a ball of reef safe epoxy putty and zip ties. They host a number of different creatures in the wild including anemones. It seems like there is no way to tell gender so if you just want two it would be best to buy a pair that has already bonded.
Thanks for the clarification. I used the term "Fry" incorrectly. ( Been advising on a number of freshwater breeding threads so FRY were on the mind
The ones that I had were of wild stock and back in the 80s. It was said back then that the babies were usually spit out around the spines of local long spine urchins for protection. In many documentaries about fish, I've seen multiple shots of baby cardinals as well as adults ( many different species) all within the spines of the urchins for protection. Obviously this is an inbred natural mode of protection that may help aquarists make their fish more likely to carry and yield some babies by duplicating. We didn't have the fake ones back then
As for sexing, I was shown that males have a longer dorsal filiment as well as using the location of the joint of the jaw for identification. Males would have the joint further back than a female and more in the black stripe opposed to at the edge of the stripe. You may be able to see that in this pic: http://www.bing.com/images/search?q=...electedIndex=3
Here is another pic I found online which was similar to a pic I received from my shipper in Indonesia regarding the fish using an urchin: bangaii Cardinal - Bing Images
With all the tank raised fishes being produced now, I don;t know for sure that an urchin ( real or fake) is mandatory when breeding or just an accessory. I would think necessity if the fish are in a community type setup tho.
Hope this helps