I had a huge Midas that used to bite the @#$%&* out of me, now my little 5" Kamfa is doing it too.....try grabbing them (gently) and they should piss off for a while, when they come back do it again. Siphon hose taller than the tank helps a lot too.....they DO draw blood and they DO have a very powerful bite @ 10"-14" mark....maybe sooner
I miss the days banging my funny-bone on the edge of the tank after trying to dodge a bite and reeling in pain while pointing and mumbling "Damn you, you little psychotic *&%^$$$#**&$##!!@&$$$***^###!!!!!!".