White fuzzy mold is not problem on wood in a humid terrarium. It's normal to see fungi and mold on wood and glass, especially with newly set up tanks. It will come and go away, eventually. You may see all sorts of stuff, like green algaes, even mushrooms. No problem. They are interesting. These aren't pathogens unless they are growing on one of your personal appendages. Wipe them off the glass with paper towels, or anyplace else they are interfering with your vision, but otherwise, just watch and enjoy. This is actually what you want to help begin a relatively biologically balanced dart tank that will more or less sustain itself without take-downs and constant interference. It's good.
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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