I've had a Cleaner Shrimp in my 29 gallon tank for 2 months. Yesterday, for no obvious reason, I found it dead, lying on the bottom of the tank in the back. No obvious physical damage or discolored areas and no behavioral changes. Levels for the tank are as follows: amm/NO2 = 0, NO3 = < 10, SG = 1.026, Alk = 3.0 mEq/L. pH is measuring at 7.8, but I'm pretty sure this is a bad test kit, and its actually 8.1 - 8.2. I did a 20% WC earlier in the day, after taking those readings. I have a Fire Shrimp in the same tank who has shown no effects either, but it has only been in the tank 1 month. Multiple hermits and snails in the tank that are all fine as well. Is there something I'm missing, or should I just chalk this one up to 'nature'?