LTAs rarely host clowns. But just a mesh lid.Do lta's actually host clownfish? (They very well may, but I'm not sure. My clowns took about a year to notice the BTA in my tank...)
Lid like glass lids? You can look into Aqueon and see if they have the right size. Or you can ask the LFS to contact planet and see if you can purchase some from them. Personally, living near Houston, I only use glass lids when it gets cold (so, like maybe 2 months out of 12, lol) since they hold in heat. My tank gets way too hot if I try to use glass lids most of the year. I currently have black egg crate on top of mine.
I've always thought glass ones were bad for air exchange otherwise I would alrety have a lid for my 75 gal.