Very nice build, my suggestion is to move the hinges to the bottom for a drop down door, that way you don't fight gravity with the doors or have a stick ready to prop the door open.
I did think about hinging the other way but just have a stick to prop doors when neccessary. No they are not ten gallon aquariums they are made from a material called tresspa. This is used widely in the uk for toilet cubicles in public places etc. Totally waterproof so suited for the humidity , two boxes of three compartments are built and then clad with moisture resistant mdf sealed with 3 coats of non toxic varnish. Perspex doors and upstand are used and a removable mesh frame sits along the top of each level creating hanging area and good ventilation. I also incorporated a cupboard with vent at back to store live foods etc with lighting . Led lights were used on each level and they were purchased from tmart.com .