I would need to know more about your tank set up, what size it is etc. However with the few comments that you have provided I would say the following.... Food is a big issue especially with fry and juveniles, dry foods do not cut it, sure you will have some that survive, but without the proper diet you are going to have losses. 2nd... Frozen adult brine shrimp has no nutritional value, and I believe that you can have lots of issues feeding that Did you know that frozen brine is the dead stuff at the bottom of the barrel that they could not sell live. Compounded with the fact that you don't know how many times that it has been thawed out and refrozen. I think it is possibly the worst food you could feed your fish.
I think it best to research the fish you are working with and try to provide a diet that is close to what they would eat in the wild. Cyps are plankton feeders, freezed dried plankton or even mysis shrimp are going to be a much better alternative. For fry freshly hatched baby brine is the only way to go and I also feed it to the adults.
I'm not sure at what age you are adding the juveniles, but it can become an issue. Trying to add smaller fish with older fish doesn't always work out either. Cyps are very territorial, this territory is virtual, and older males can be very intimidating.
It only takes a few things to go south, wrong foods and tank mates are the usual suspects. Once a cyp is stressed or can't claim a territory then they go nuerotic on you, stress is the biggest cause of the bloat.