I have lost 2 tangs, angel, full grown chromis, blue spot jawfish all in the pass 2-3 weeks. I have only found two body's and the were in tact but all the guts gills and eyes were missing and full of a thick mucus and really stunk. I have no snails or hermits in the tank. Have 2 cleaner and a peppermint shrimp and a sand sifting star. Have heard no clicking in tank so don't expect mantis. Any suggestion would help. I am taking tank apart tonight or tomorrow and looking in all the rocks. Tank has been up for 2 years and newest fish had been in tank for 3 months.

Sal .025
Ammonia 0
Nitrite 0
Nitrate 20 normally 0 but guessing high due to deaths
Ph 8.2ish
Calcium 380
Dkh 9