How do you get black algae off the fish tank?

I tried my trusty algae scrubby, and it doesn't work.





Is there a secret to it?


I've never had black algae before... I've never HEARD of black algae before.





What causes it?|||Black algae is just a different kind of hair algae... and it's considerably more persistent. If it's on the glass, try using an old credit card, razor blade, or ice scraper to remove it, and then siphon it out. If it is on a decoration, remove it and do an overnight bleach soak. Let the decorations dry for at least 24 hours so the bleach can dissipate (the chlorine in NaClO will diffuse into chlorine gas in the air). To prevent it, you'll need to keep your nitrates and phosphates down with water changes (if there are nitrates and phosphates in your tap water, use RO water), and consider reducing your lighting (especially if you don't have live plants). Consdier getting some fast growing plants like Water Sprite and Hornwort to at least slow (if not halt) its growth, as they will quickly outcompete it for nutrients.





If you have a fairly large tank, you could try Siamese Algae Eaters, but I have found mine to much prefer any frozen food I give it (it is particularly fond of brine shrimp). Also, I have heard recommendations of adding Flourish Excel, but this is only applicable if you have live plants. The carbon source will allow the plants to use nutrients more efficiently, again, outcompeting the algae.





EDIT: Snails won't touch the stuff, nor will they do anything for other kinds of hair algae. You could try turing off anything that creates current in your tank, then squirting 5 mL of hydrogen peroxide directly onto the afflicted areas (no more than a couple of 5 mL doses per 10 gallons every couple of days), but this is very dangerous for fish if they swim through the peroxide cloud.





EDIT 2: While some fish may mouth it (in search of real food), Clowns and Catfish will definitely not eat it (intentionally)... Silver Dollars might pick at it a bit, but they certainly won't be an effective means of controlling it.|||i have it growing on my decorations and i think it looks cool but i have alot of current in my tank so it sways and adds character to my tank, as for it growing on the glass use a car ice scraper, works for me. also i see my clown loaches, silver dollar, and my little catfish nibbling at it all the time so its probably good.|||to help with that, clean it off first, then change the water,,if anything,,never leave the light on, only during feeding, and maybe a hour or so after that...|||get some snails... i think they will work..