I'll start by saying I do not breed fish or attempt to. I do know that fish commonly eat eggs and even fry once they are free swimming and extremely small.
It would depend on the mesh. Will it hold eggs? Is it located in your main tank? I'd cut the leaf off to obtain the eggs.
I knew a guy who used to breed several different types of small schooling fish. He would use Mason type jars with the screw on lids. He would place several plants and moss in the jar, add tank water, add the eggs, and close the lid on the jar. He'd keep the water about an inch or two below the top of the jar so it floated in the tank. He'd leave it for a week or so until the fry hatched. Then he'd move them to a small 5g QT tank and feed them crushed up flake food....maybe even brine shrimp??
The idea was that the plants he'd put in the jar contained microorganisms that the fry could feed off of during the first week to week and a half. It also provided cover from light.
This is probably the rough draft of what I saw him doing and why but it seemed to work for him. There's guys on here that are proficient breeders who could give really good advice.