Oh, I didn't say it isn't pretty, but its beauty is only skin deep. Hair algae is extremely invasive, and will completely over run you tank if it's not kept in check. It's the #1 cause for tank teardowns for a good reason. It's very hard to get rid of once it has spread over a good area. I've been battling it in two tanks for over six months, have extremely low nitrate and phosphate levels, pluck it out as much as possible, and yet it persists. All I manage to accomplish is to keep it "contained".