My tank is 3 x 2 x 2
the water parameters are within acceptable range as all the LPS are healthy and open and some have been in the tank for many months. The other fishes are very docile ones like fire goby, lemon goby and yellow wrasse.
Actually, my main suspect is a large bubble - could it stung the angel. It looked pretty shocked one day b4 it died. Other than that, it has been healthy and greedy, devouring everything that I fed it....