I think its algae, but I'm not sure. I wiped off most of it with a paper towel, I just stuck my hand in the tank and wiped it clean. But now its starting to grow more and more and I can even see it on the white rocks in the front of the tank. I'm not sure why it is growing only in the front as well. You can't see it too well if you look from the outside, hence no picture, but if you look directly down at it you can see it. It's just starting, I don't want it to get out of control.
The tank is not in the sun but I think it might be because I leave the overhead light on 24/7. Or maybe because I didn't clean the rocks good when I did the water change last time. Opinions? THanks!