strange question....reguarding silicone

just notice that a couple of my mollys like to nibble on a small piece of silicone that seals the edge of the tank...it looked almost like a cat claw piece hanging off...

i went a head and cut most of it off...but there is a small little "pimple" (for lack of better word) left of it...so far i havn't seen them nibble...but the question is could this potentially hurt them?

anything else i should do?

thanks