Hello, I have a 10 gallon with 4 male guppies and 4 lamp eye tetra along with 3 ghost shrimp and 1 chinese algae eater aka sucker loach.
My blue guppy became sick that night because I noticed he wasn't swimming around, I figured it was nothing. The next morning I awoke to find him with this huge bite mark which ripped half of his tail body off.
I posted this on my other website and many folks think the culprit is the chinese algae eater. They say that the sick guppy was probably not strong enough to avoid the Chinese Algae Eater and he got a good sucking out of him. I do believe it was the CAE because the tetras and shrimp would not have good enough teeth to do this.