HCA: Hermit Crab Association

So I've been away at college lately and my mom has been feeding/giving the crabs fresh water. I come home about once a week and check on them and clean up the tank. I am seeing weird fungus growing in one corner of the substrate that wasn't there a week ago. They almost look like little mushrooms but there's a couple spots with a little bit of green too. My substrate is plays and and eco earth along with some worm castings mixed in. The tank doesn't smell weird or anything but I'm really worried what that stuff is and if it can hurt the crabs. These are the images I took of the stuff.

Edit: I've dug one up and they are in fact mushrooms. If I smell one it does indeed smell mushroomy but only if I put it up to my nose, other than that there is no smell when digging them up other than normal earth smell.

Okay I've now removed all that were visible, I couldn't dig around much other than that since I have one crab molting right now. I'm worried they'll come back if mycelium is still intact in some spots. Could they be poisonous? They appeared to be white with brownish caps.

There is no way to know if that fungus is harmful to crabs. It likely will come back now it's established - try removing the fruiting body when you see it. Apart from changing the sub, or dropping out of school to keep tabs on the fungus ( ) I doubt there's much to be done.

Vinegar is crab safe, and I believe is a natural anti-fungi treatment. I'd just LIGHTLY mist the area with vinegar, and hopefully they won't pop back up. That being said...I'm by no means a fungi expert, and I'm not sure on the effects they may or may not have on the crabs.

Alright LadyJingly I see that the real solution is a become a full time stay at home crab mom. I will try the vinegar misting Rawrgeous suggested next time I can go home, hopefully it works. I'm wondering how it even got there, and underground only and just one corner. I have fed them store-bought mushrooms before so maybe somehow there were mushroom spores that came off of it and spread? I have no idea if that's how mushrooms work.

Stay at home crab mom! Problem SOLVED!

Spores is exactly how they work - and spores can get on things you put in the tank, being often airborne, or common in the environment around us. If you harvest wild plant for your little guys, it could have even been that. Moist sub is good growing for them - especially if you add worm castings.

The may be edible, but it's maybe best not to check.