Yes. Cheese will mold at room temperature, even if it is in a container. It will mold faster at room temperature than it will in the refrigerator.
It would depend on a lot of things. One I am certain of would be the temperature that the cheese is in. Others would be: the type of cheese, air exchange, humidity, and whether light was present.
Get the moldy cheese and use it in the room with the robot mouse.
Kind of cheese brand of cheese where the cheese is put the room temp for the cheese
get the moldy cheese from the basement of the castle and lay it out in the bed room
In the refrigerator. It will get moldy if left out at room temperature.
In the Maid's room (castle first floor left), feed the cheese to the robot mouse.
you put it in the room with the mouse in the astro knights castle and the mouse will eat it
If you mean Poptropica, you can get the rat when you go to the castle and go to the left door, give the Moldy Cheeseto the rat, and he will come to you.
There is no fish. You have to get the mouse from the madian's room and feed it to Merlin. You lure the mouse with the moldy cheese you get from the dungon.
In the Maid's room (castle first floor left) you will find a mechanical mouse.
Most cheeses are solid at room temperature.
Some Vacheron mont d'or French cheese does.