I have two 55g tanks in my bedroom, one is my peacock tank and has glass lids under the canopy, the other is my mbuna tank and has a canopy but I never bought glass lids for it. Well last night I was having trouble sleeping (which turned out to be a good thing!) because about 5am I am laying in bed and I hear what sounds like a "wet flopping" on the wood floor

It's amazing how tuned into these things our hearing can be lol. Anyway I jump up and turn the light on and there's one of my 4" labs on the floor. I quickly grabbed him and put him back in the tank and he is perfectly fine now but I need to keep it from happening again.
Obviously the first thought is glass lids but I do not want glass lids on this tank. Reason being is one of my other hobbies is that I keep/grow Bonsai trees. Bonsai trees need high humidity so I keep them on top of my canopy on this tank which works out perfect with the humidity this room gets from the open tops on the tank. So I don't want to use glass lids and negate the humidity from the tank.
I'm thinking maybe going to Lowes and getting some light diffuser panel (egg create some people call it) and cutting it to fit the top so it keep the fish in and still lets the humidity out. Just wondering if there are any other ideas that might be better?