Pond Boss Forums INTRO Questions & Observations algae bloom

Filamentous Algae

FA is like most aquatic plants, "good" vs. "bad" depends on how much you have wrt your goals for the pond. IMHO the most common complaint about excessive (in the eye of the pondholder) FA is aesthetical: unsightly appearance and making the pond undesirable to swim (or fish) in.

Huge amounts of FA, like other plants, have the possibility of dying and causing an oxygen loss fish kill.

FWIW you don't seem to have a whole lot of it. The photos in the linked thread (particularly the ones of submerged FA) should help you idenitfiy if that's what's green in your pond.