Homemade Cory Egg Trap?

[coyemuse]

How do I make a cory egg trap. and how do I get proper ventilation on it? how do i keep the eggs from getting fungus?

 

[Peter C]

I cut a 2 litre bottle of pop (sprite, coke etc) about 4 inches down from the top

Like so

Held onto the tank in the corner with 2 large paper clips. I put fresh water in daily, had about 30-40 eggs hatch roughly, can't really count how many iv got or how many iv lost as they are tiny and fast! But iv got loads. Got a moss ball in their for them to eat from, also got an air stone in their

Other than that they seem to be doing fine