Newer SAP Tank Algae - Advice Please

[ATXpuffer]

So against the odds apparently, I successfully cycled my 15g tank with my SAP in it, as well as three gold zebra danios and an upside down catfish (who disappears for days at a time). Now, the tank has been up and running for coming up on two months, with the SAP in it the whole time, the danios were added about three(ish) weeks ago, and the upside-down cat has been in there for about a week and a half. Additionally, there is a small live dwarf sword plant of some sort in there.

The issue: My fake plants (not the live one) have started growing a rust-colored algae on the upper "branches", and there are a couple small spots of the same stuff on the back tank glass. The growths are spotty, and have spread in the past week.

So what is this gunk? Is there a way to get rid of it? Is it harmful? Any advice from people who have experience with this is much appreciated.

[Pufferpunk]

Sounds like diatoms. I'd say to add a school of otos, but your tank is already way overstocked & you will probably continue to have problems with it.

[ATXpuffer]

How is it overstocked? I have an inch long SAP (that is hand fed at every meal - no big food chunks left in the tank), and three small danios that are fed sparingly, and a cleaner fish that eats leftovers from the substrate. My levels are fine, and my water is crystal clear. I've had no problems with the fish fighting at all, and the live plant would logically only serve to lighten the bioload in the tank. What makes this a WAY overstocked tank? As is, I've got about 3 gallons per inch of fish, conservatively.

Are ottos the only solution to diatom algae? Would reducing the light cycle duration help?

[J-P]

library/water-filtration/brownalgaediatoms/

[ATXpuffer]

Hey thanks j-p! I guess I'll just wipe that scuzz off and hope that in time and as per the article it just subsides over time and tank maturation.

At the risk of sounding like I'm trying to start an argument (which I'm not), I'm curious as to how my tank is overstocked. I've always heard that one or more gallons per inch of fish is adequate, and I've made sure to triple that number due to the messy nature of the SAP. When time and money allows, I'll set up a nice 30 long for the current crew and fill it with plants, but until then, what harm is being done? I'd like to hear back from PP on this, because I know she has years of experience in this hobby, and anyone else who feels that I may be misguided in my current setup is more than welcome to contribute constructive criticism as well.