One of my young Endlies tried eating a clown loach.... actually had it in his mouth when I found him.. not sure if he would have let it go or not once it hit the eye spine, tbh i wasn't going to find out. problem is ime is if a fish tried to eat one.. they easily get lodged in a fishes mouth because fo those eyes spines and can result in killing both fish... if the predetor is lucky they will spit the loach out and usually both are fine and the whole incident isn't even witnessed, and lesson learned. I've seen an Oscar, an arrowana, and heard stories of other predetors haveing this issue. granted it is rare and I can count on two hands how many times i've seen/heard of it in over 10yrs working in lfs ect.. so hundreds of customers/tanks , so not common by any means. But it does happen.