I will post a pic, but it isn't a very good one, so maybe I can describe it to you guys? It seems to be a series of rust colored splotches (is that a word?) on the inside tank walls, on the gravel and even on the artificial plant.

I am assuming it is some kind of algae? I thought that snails and catfish cleaned that kind of stuff up? Of course, I am new to this hobby so please correct me. If they won't, is there a kind of sucker fish that will clean the tank walls in a freshwater tank? How hard are they to keep alive? If there is NOT a fish, can this harm my tank? How do I clean it?

Picture:

Diatoms. It is a type of algae growth. It's normally found in newly established tanks but can appear as far away as a few months after setup.

They do go away on their own eventually. As for fishies that take care of it...Otocinclus Catfish is the main one. These little guys are sensitive in general. You will have to suppliment their food with fresh veggies if you decide to go that route.

Oh..and as far as cleaning it...it just wipes right off with little effort. You can simply use your hand or a scraper if you prefer.