cut the bottle in half, invert the top half. You may want to leave the cap on with a hole just big enough for the fry. Once they find their way in, they typically don't find their way out. I'm using that trap at the moment to get some of my cherry shrimp!
I'll be heading to the LFS today to get some store credit for a bunch... apparently $1/shrimp in store credit.... I have hundreds!
Maybe this is how I'll save up for my SW tank
. Sorry for hi-jacking. haha.