I have a 10 gallon FOWLER tank and when I was checking on everyone/everything just now I noticed what looks to be a mushroom growing at the bottom of the tank.
Any idea at all where this would have come from or what it is?
If you added live rock to your tank then you end up with hitchhikers, this can be inverts like sponges, crabs, snails, worms, starfish, as well as the occasional coral.