DIY Jump Guard?

[Aqua sobriquet]

These things seem quite expensive for what they are so I’m wondering if anyone has made a DIY version?
I’ve been contemplating getting a 90P but I’m worried about over enthusiastic Corydoras getting out. My current Nano has a glass cover but I’m worried about the aesthetics of using glass for a 90P?

 

[AlecF]

In my experience corys rarely jump if you have floating plants. If you were to lose any other reasons would be more likely.