Everything I've read about having fungus gnats in a terrarium talks about what a pest they are. Harmless but annoying! Well I just discovered one reason to enjoy having them. As their name implies, they eat mold! I had a small patch in my terrarium and just as I was about to remove it I saw it crawling with fungus gnats so I left it over night. The next morning it was totally gone! And whenever clean out a poop it's usually crawling with fungus gnats. They may not be as obvious of a cleaner insect as spring tails or isopods, but they definitely seem to do a good job! I definitely and willing to deal with gnats buzzing around my plants and terrarium if that means they'll be cleaning it! Anyone else experience their helpful nature?