I just noticed something growing on my plants today and I'm not sure what it is. It's not on any of the plants in my 29 gallon, but is all over the plants in my 55 (both real and fake). If I didn't know better, I'd think it was a spiderweb or cobweb of some sort. I've got hornwort and it circles the entire plant. Also, my gourami was picking at it too. I'm guessing it's an algae of some kind?