When peering in at my Amazon Milk Frogs the other night, I noticed a mushroom like fungus growing out of the substrate (pics below). The terrarium is a 18x18x24 zoo med terrarium, 3inch hydroton, 2inch coconut fiber substrate, 1inch sphagnum moss. All live plants and it has been setup for about 4 months, and I spot clean weekly.

Can anyone identify the fungus?

Is this dangerous for the frogs?

If so, can I just pluck them out as I see them, or should I re-do the entire terrarium?