Light Causing Alge?

[FordForever]

I have these nice smooth flat rocks in my tank, I found them in Georgia. One is laying flat and the other is on its side. On each rock the upwards facing edge has a lot of yellowish alge on it. Is my light causing this growth and is it harmful to my fish? My levels are absolutely perfect I just checked them last night.

I can get pics on here later tonight.

[Lady Hobbs]

If your tank is fairly newly set up, this is common in new tanks. It's called diatoms and will stop once your tank has gotten established better.

[FordForever]

Yes my tank is only a month old. Thanks!

[travie]

Don't worry, it isn't harming your fish either.