Black spots

[Lfaletic]

Hi everyone, Lee here, new to this forum. I have a 55 gal fresh water aquarium with four cichlids. There is a lot of rocks and numerous plants. Mostly Java fern, Amazon sword and Anubis. I’ve had this tank set up for about 11 months, so it’s vary established. I do routine water changes when needed. Parameters have been pretty good. I get minimal algae on glass. I also have 4 Octos. I also dose with Aquarium Co-op easy green.
My problem is black spots and streaks on Anubis leaves. Only the older leaves not the new ones. The black doesn’t rub off and appears to be part of the leaf. Otherwise leaf appears vary healthy. Can anyone give me any ideas of what spots are and how to treat in need be? Thanks so much for your time.

 

[Aiken Drum]

Its algae. I get the same on my anubias as the leaves get older it accumulates and is difficult/ impossible to get off. A toothbrush gets it off to some degree, but once it sets in to that level on my anubias i can never really get the leaves completely free of it.

I dont think the leaf on the top photo would ever lose that dark green colouration no matter how abrasive cleaning you gave it. But i think the spots on the bottom photo will come off if you used a toothbrush on the leaves.

This is why i attach anubias to lead plant weights rather than to the aquascape so i can easily lift them out and clean the leaves.