need an idea to use to weigh down fishing line...

im making a mobile thing for my cousins baby shower this weekend. i found it on pinterest but improvised a few things to what i had at my house. instead of string i used fishing line but now the butterflies i have on it arent sitting right, i thin its bc of the line when i pull it down straght the pop up and are how id like them to be. so now im thinking i could put some sort of weight at the end of the line..but not sure what i could use/make.

any ideas? preferably something small.

Uh ... a bead?

i thought of that but dont have any=/ should have posted that.

Can you add some thickness somehow to the butterflies?