Draining the water - without sucking up the fry?

Some of these babys are so minute (esp Betta fry), that even if I cover the end of the siphon hose with a silk stocking, they still manage to get through...

I put the submerged end of the hose through the cap of a plastic bottle - tight fitting (cut off the bottom) and cover the bottom with a silk stocking.
Any suggestions?? How do you do it??