Only because of poor ventilation, if that is the case. Living in air dense with spores 24/7 may take a toll on their well-being. If upon opening the viv you find it smells strongly of mold instead of clean earth, get more ventilation.Is there any danger for my pair of thumbs from this crap.
Is it possible it could be saprolegnia fungi? That's what I was thinking. It seems to originate behind the space where the brom is fitted into the plastic tubing.I am pretty sure these are fungal hyphae, the mass of mushroom that usualy grows underground. As mushrooms are a great food source for many soil microfauna (including springtails and isopods), I would view the hyphae as a positive occurence. I don't think there is much chance of a frog being caught in this.
Take care, Richard.