Every time I raise a batch of young Cyps, about half of them never make it to adulthood. The ones that make it to adulthood are healthy and always ready to eat. The ones that don't make it slowly waste away. They seems to be interested in food but are more timid when it comes to feeding time. Whatever they take into their mouths get spit out. I have searched on the web and read through several forums. Even though many others are experiencing the same wasting-away phenomenon, there does not seem to be consensus on the cause. Some speculated that it is caused by internal parasite. Some believed that Cyps require additional nutrition over and above what is available in flake food. BTW, I do feed frozen brine about 2-3 times a week to supplement flakes. I also do 40% water change once a week.
I suspect that the Cyp is a very nervous fish. In the wild, it is possible that Cyps of similar size stay together. In the aquarium, it is not possible for smaller Cyps to avoid the bigger Cyps. Therefore, the smaller ones get intimated and they go into stress. Once stressed, they cannot keep food in their bellies and start this wasting-away process. I don't have room for more tanks now but hope to add at least one more next summer to prove my hypothesis. But if you can shed some light on this problem, I will appreciate it very much.