i'm glad someone made this thread. i never thought i'd end up with a tail biter! i still don't know what triggered it.
he had slight fin rot when i brought him home from the store so i QT'd him in AQ salt for 10 days, then returned him to his tank.
but, i have to say that i did accidentally drop him in the sink once while changing his AQ salt water, and i shut the drain, which tore his anal fin, but it wasn't really major. it's fully healed now.
after about two or three weeks from then, he started this:
then, about a month ago from now, i saw this when i came home from school:
gosh, i was just so sad.
he currently looks like this:
you can see the parts where it's growing back. i hope he doesn't do anything else major. every week when i do his 100% water change, i move his decor around in hopes of deterring his tail biting.