When I first took home my Argentea, he dug a pit around a piece of wood. I went to move the wood and got bit pretty damn bad. He hasn't done it since though.
My betta bites my finger when I "finger feed" him. After I moisten the pellets they stick to my finger and I dip them in. Doesn't hurt at all though, obviously.
lol my oscars are starting their "breeding mood" and today when i did a water change, they decided to DO WORK on my hand when i was cleaning "their area" lol, nothing major, just some scratches, but some if it did hurt.
my P.Bass scares the S*** outa me when im not expecting it. No blood, they stalk me from the other side of the tank and nail my hand if its at the surface
My Red Devil has bitten me alot,as a baby fish he would grab arm hair and tugg it while i was in the tank.. This was cute now at 8-9 inches it draws blood,still love the fish but i am paying attention to wheres hes at now. Also as a question the burning sensation you sometimes get when bit,is that from the tank water amonia /nitrtes or the fishes mouth bacteria..