Losi, you should watch your fishes. If you find cory who has lost he's eye then you know who did it - clown loach. 3 different botias are quite wicked fishes, macracanthus, striata and lohachata. I wouldn't put macracanthus and speacially striata with cories. B. lohachata is more peaceful than others...
I have seen writings that cories has lost their eyes when they are kept with clown loaches. Some hobbiest told that clown loach has plunged into shoal of cories and after that hobbiest found one cory without eye.
German "fish-guru", G. Ott, has warned about this. He even advice to keep loaches, especially B. striata, in sort tank.