A patch of this blue filamentous algae just popped up, I don’t think I’ve ever seen it before. It kind of looks and feels like green hair algae (which I also have some of right now) but it’s a striking blue color and has a bit more of a feathery pattern. It is definitely not the blue/green version of cyanobacteria. For reference the strands are up to about half an inch long at this point. It’s actually pretty. I’m wondering if anyone knows what algae this is, and whether or not I need to worry. I don’t generally get too worked up about algae as long as I know it’s not something super-aggressive, just manually remove once in a while.