I agree with Byron as well
I would watch the Kribensis as potential culprits. I recently purchased a pair of Kribs for a tank with 3 Dwarf Neon Rainbows, 1 Angel, 2 corys, 3 Bolivian Rams. I know better, but read up on a species before you buy it. I have 5 fish which are relative bottom or low tank dwellers in a 30 gallon tank. Kribs can be bullys regarding territory and food. Particularly to the lower dwelling tankmates. My corys and the Rams have taken a beating because the female Krib controlls the tank. She actually took the eye out of one of my corys. Had I done my reading, I would have seen all the recommendations not to put Kribs in with lower dwelling less aggressive species like the Rams or the Corys. I would have also seen not to put them with fish smaller than themselves. I also no longer keep Chinese Algae Eaters because as they grow they become less interested in algae and more interested in the slime coating of the other fish. Just some food for thought on stocking considerations.