I have little pockets of brown algae on my gravel and on some of the decorations. When I scrub it, it comes off, but I'm concerned as to why it's brown and not green. My substrate is white gravel so it really sticks out. It's not too bad but looks like blotches of blood.
Do I just need to scrub this out or should I be concerned. My water parameters are excellent and my fish are fine.
Oto cats love the stuff. I used to have it all over my tank, then I added a couple otos. Now the only place I see it is in the filter return where the otos can't get it.