| | Re: Juwel 180, Long'ish Brown Aglae Threads. Inc Photos
That looks like a type of Cyanobacteria. Red brown in color (redder than diatom).
Soft & slimy, very easy to pluck off. Can be 4 inches long if the condition is right.
I've found high DOC (dissolved organic matter) causes it.
Frequent water change, clean filter help. Some of the strands will turn pale or white
when it's receding.
BBA is strongly attached to the surface, not slimy and not that long.