My first poison dart frogs were lost due to escape, and subsequently I am paranoid about the vivarium being completely closed, the previous tank was a 55 gal with a steel mesh cover, with screen added as well. Regular routine maintanence and feeding usually requires opening the lid, what I have done to cut down on the opening, at least for feeding is to add a "feeding tube." 3/4 inch pvc pipe, painted black to make it less noticible is put through a hole in the lid, a flange on each side holds the pipe securely. A 3/4 inch pvc cap is removable for feeding and a funnel spout fits nicely. The flies end up in the same area every time and the frogs already know where the food is every day.
I'm keeping my four leucs in a large critter keeper. I like the fact that you can open it without opening the whole lid, but having to wrap the lid in plastic wrap kind of defeats the purpose. Then I got the idea to fully cover the lid with the wrap. You take a really, really long piece of plastic wrap, lay the lid bottom up, then lay the wrap on one of the edges, run one side of it through the door opening, and the other side on the outside of the lid, so that the bottom is covered a flat sheet of plastic wrap. Tape the sides to the top of the lid, and continue around until the whole thing is covered. That way you can have it covered with wrap to keep the ventilation down, and still open the door to care for the frogs without having to take the whole lid off. I can provide pics next time I do it if anyone would like to see it illustrated.