I set up a 60 cube with eco-rock, cycled for 2 months or so with damsels and decided it was time for some cooler fish. Water tested perfectly before I brough home a pair of tank-bred clowns. They were doing great - eating mysis and flake, no signs of stress - for the first week and a half. All of a sudden, I found one dead some morning. The other disappeared two days later with no indication of sickness or distress. They were the only fish in the tank with some hermits and snails.
Any speculation as to why the sudden deaths?