Okinawa is hot and Okinawa is wet. It rains a lot, and it's very humid. 30° temperatures with 80-100% humidity is of course perfect conditions for moulds and other fungi.
Hazy, wet summer day. It's not "real" rain; it's just so humid the water starts to condense right out of the air.
Everything here will grow mouldy within days unless you're careful. Dry foods, cutting boards and kitchen tools, window seals, laundry, even stainless steel racks — anything with dark cracks or hidden corners can go mouldy within days or hours.
The bathroom is easy: scrub the shower and bathroom with anti-mould spray once a week (and the bathroom gets all nice and clean too). But you can't use those anti-fungal chemicals in the kitchen or on dry goods; all you can do is clean often, and try to keep things dry.
Foods go bad quickly. Once you've opened a sealed jar or bag, store it in the fridge. That includes dry pantry goods such as pasta, flour, rice, spices and tea. Salt is safe from mould but will turn into a solid rock from the humidity, so that, too, goes into the fridge. Bread and coffee beans go into the freezer. There is no such thing as a "too big refrigerator" here.
You need to air all bedclothes, including the mattresses, every day, or they'll get mouldy; floor mattresses are better than beds here. You don't want to leave wet laundry in the washing machine or it'll go bad within a few hours. A washing machine with a timer and an unheated air-dry function is a really good idea.
We got a dehumidifier for the bedroom/work room last year, and that's perhaps the best thing we've ever bought. We leave it running all day, every day when we're not in there. We try to keep books and other sensitive things in that room, and so far we've managed to avoid any water damage or mould.
Camera gear is very sensitive. Once you get mould in a lens, it's ruined — the mould permanently damages the glass surfaces, and you can't ever really get it out again. I keep the gear in the bedroom and so far the dehumidifier has kept it clean. Still, I may have to get a separate dry-storage cabinet at some point.
I think we'll also need to get a second dehumidifier for the main room. It's not as critical as the bedroom, but better safe than sorry. A bump on our electricity bill is a lot less painful than trying to remove some black mould infection out of the couch.
I keep thinking, though: in aquariums, people keep catfishes. They happily eat the algae that grow on the glass and rocks, and keep the aquarium clean while being a cool inhabitant. And people keep goats to remove weeds and brambles.
Isn't there some animal that similarly eats mould? Perhaps something cute that you can keep as a pet? Any geneticist our there looking for a nice, flashy project might want to take notice and try to produce a catfish-guinea pig hybrid or something. A glamour-mag publication is almost guaranteed — if it's cute, you might even get the cover!
Ah well, until the happy day when Rodney the Guinea-fish arrives to lick fungi off our apartment walls (while emitting, I imagine, happy chirping sounds), we'll just have to keep after it ourselves.
#2 The plural forms "octopuses", "octopi" and "octopodes" are all considered correct, either due to grammar regularity (octopodes) or actual usage (octopuses and octopi). The others, not so much.
#3 Yes, they fly. But they're pretty small, slim and silvery; nothing like the regular squat, wide, brown cockroaches. I honestly don't mind these much.