Take some pictures and post them. In the meantime, don't worry. You cannot avoid algaes (green) and molds and other fungi, (white and other colors,) in a humid set-up, no matter what you do. They will occur in any natural environment that suits them, whether you have previously attempted to sterilize it or not. They are a part of the process of biological recycling, and that's what most of us into darts design our tanks to do. These things you are seeing are not pathogens. They will not harm your dart frogs. Wipe the extraneous stuff off of the glass so you can see better, but otherwise, leave it alone and just enjoy what is happening. When you are working with something between 80 and 100% humidity, which is what darts prefer, some very surprising things may grow. They help recycle frog poop, and generally keep the tank more healthy than it would be without them. My tanks are full of algae, mushrooms (mushrooms, only at first, alas, because they are so great,) fungi, and my only dart frog losses have been from escapes, one injury and only one unexplained in six years. The oldest have been living for 6 years with all of this stuff going on. Some of the tanks have tiny snails, centipedes, isopods, and strange tiny worms that I think are some kind of beetle larva. They are often "infected" with fungus gnats, that the frogs eat up, other strange, small critters among the moss that the frogs also hunt for. I just don't go into a panic everytime I see something in a tank that has not been there (or I haven't noticed) before. It is not likely to be some kind of dart frog parasite. I do a minor clean up of slugs. I remove them when I can catch them and sometimes bait them with beer when they piss me off by damaging leaves. The frogs won't eat them and they can do some plant damage, so I generally don't like them. But I'm not going to take down the entire tank over a few slugs. I just pick them off and bait them. These also seem to come and go in a cycle.
You may lose some inappropriate plants for a humid environment, or those that have been planted in the wrong section, so if a plant dies, just remove it. If it's full of mold, it's not the mold that killed it, but the fact that it was inappropriate to the environment you put it in.
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Patty
Pahsimeroi, Idaho
4 D. auratus blue
5 D. galactonotus pumpkin orange splash back
5 D. imitator
6 D. leucomelas
4 D. pumilio Bastimentos
4 D. fantasticus
4 P. terribilis
4 D. reticulatus
4 D. castaneoticus