Plants are mentioned, so this puts us in a specific course to deal with BBA. In a planted tank the cause of problem algae is an imbalance of the light/nutrients. We need to provide the light intensity and duration in balance with the necessary 17 nutrients for the plants; this thwarts algae, and is the only effective and safe method. Algae-eating fish will not eat BBA (there are two species that will, but both have specific needs and issues making them unsuited to most tanks, and certainly any under 4-5 feet in length). Otos, Bristlenose plecos, Farlowella, etc will not eat BBA.
Never use any chemical treatment; I know there are those who say it is safe, but it is not safe. Hydrogen peroxide is a powerful oxidizer that has been used under field conditions to control I. multifiliis. High doses can cause gill damage leading to fish mortality (especially at high temperatures) (Schmidt et al. 2006; Noga, 2010; Picon-Camcho et al. 2011). Correct the cause rather than risking the biological system.
Data on the light and any plant additives/fertilizers will help us work this out. I should mention that in my 30 or so years in the hobby, this is the only problem algae I have had to battle (and more than once), and once I understood the cause, it disappeared and has been absent for six years now.
