What's This On My Anubias Nana?

[Valyrian]

It's like specks of dark green sand. Is it algae? I don't think algae grows in specks like this though.

 

[TwoTankAmin]

Its algae.

 

[Liam]

Yeah its algae, when new leaves grow under water they tend to be able to resist it, from what I have seen. If its not really hard green spot algae, (which I think it is) you can gently scrub it off.

 

[George Farmer]

It's Green Spot Algae (GSA). Very common on slower growers, especially Anubias. Potassium phosphate (KH2PO4) can be used to good effect providing you have sufficient plant growth and biomass to deal with the PO4 levels.

If Google "anubias GSA" you'll get a few hits.