I have 1 Derasa (2 yrs) and 1 maxima (1.5yrs). They have lived with Koran (1.5yrs), flame (1 yr-died during change to new tank). There is also 1 flame back ( 2months) and 1 cherub introduced into the tank. So far no sign of being nipped.
Sebastian
No scraper used. Noticed silicone was soft on edge when touched and it's not totally glued to glass. Have called tank maker. Will decom and let them redo the silicone