Hi iv had my red fire shrimp about 6weeks he was absolutely fine feeding, also malted about 2wk ago iv come to do a 10% water change today he was absolutely fine, done that, fed the fish in the tank live brine, about 2hr later iv come bk to clean the outside glass and he was on the rock on the outside (he normally in his hole in the rock) and I thought he looked like he was in a odd position (hanging on side) gone to toilet come back and he fallen off the rock and now laid on his back upside down, got my net in to check him and he’s died I just don’t understand why just so random, any suggestions welcome pls? Iv done a sanity test and that absolutely fine, temp water is fine,