I have a problem I can't solve. Over the course of a few weeks I loose all shrimp and hermit crabs that I put in the tank. The tank is a 6 month old 120 gallon reef with, deep sand bed, good sump, halilde lights, cured rock, good water flow and protean skimmer. Temp stays at 80. Water quality is always good/ stable for nitrate, nitrite, ammonia, pH, salt. I do monthly water changes. The fish (tang, clown, gobi, damsels) all are rock stable and look happy. The soft corrals are doing well. Everything seems fine but slowly the shrimp and crabs disappear. Someone suggested a mantis shrimp. I haven't seen anything. No crushed shells or clicking sounds. I am ready to try a trap. Suggestions on type, bait or technique? Any other suggestions of what it might be? Thanks for any help.
Harry
Harry