ok so i put this in the newbie section as i feel I'm a novice breeder. what i'm attempting to do is make a mop for a trio of mine to lay their eggs in. it's basically just a nest of yarn designed for fish to hide eggs in out of harms way. has anyone had any experience with this? what have you used to weight it down in the water? what methods or techniques work best so it wont unravel? what kind of yarn did you use? any advice is greatly appreciated as i have a general idea how i would like to go about this but want to build from others ideas as well.

I haven't made one, but I think you can make a tassel out of acrylic yarn.  Paul/Coupedefleur made some once and used corks to float them.