Kendallg, thats a tough question. Yumas imported from the wild can be tricky for most hobbyists to get established. Everyone on here who keeps Yumas is familiar with Yuma meltdowns. I am getting better with Yumas and their problems in the initial stages of adjustment but my loss is greater than my wins. You have provided no info about your tank. The fact that you bought 100 lbs of live rock suggests to me that it might be rather new? Lighting can be critical in the initial stages if they are ill. What kind of lights are you running on this tank? Is your hydrometer accurate? Whats your salinity at? How long was awhile ago? What kind of acclimation did they go through?
Without much to go on I'm going to suggest this. Make sure your tank salinity is accurate by recalibrating your hydrometer or if you use a cheapo, buy another one. Once you determine what your salinity truly is, if it's wrong, adjust it to where it needs to be slowly. Do a water change, 30 percent. Water change to the current salinity level of your tank. Do not try to save a step by modifing it too greatly if it was off. Photo period, cut it in half for the next several days. You can normalize the photo period sooner if you see rapid improvement. Clean and isolate the ones that are in dire straights. A turkey baster works wonders. Don't blow the acidic slime around from them, suck it up and drop it in a bucket to be disposed of. Feed the Yuma's that are not on the ropes immediately. For this, turn off temporarily all major current flow. Use frozen mysis shrimp or rods reef or a suitable substitute from your local LFS. Target feed only a little to each. Some might not eat and you don't want excess food in the tank. Those that do eat, remember them. Feed them every other day for a while. Those that didn't, remember them. Retry them every few days, unless they are going downhill. Ensure that your Yumas are not in a location where they get alot of the tanks current flow, it stresses them. I'm probably forgetting some things you can do but I'm not really sure whats going on so I'm giving you the standard stuff.
