Cyano or Coralline

[skunkiebeer]

Is this dark purple stuff Cyano or Coralline? It’s not hairy and doesn’t come off when I scrape it with my finger nail. My tank is over 2 years old and this stuff doesn’t look like my lighter colored coralline. I’ve never dealt with Cyano so I’m kind of panicking. It’s on some of my live rocks but not on the sand bed.

 

[Scott Ulrich]

Coralline. cyano usually tends tends to grow on glass and sand before rocks and tends to have bubbles

 

[threebuoys]

Coraline is my vote.

 

[Uncle99]

If it don’t blow it ain’t Cyano, it don’t hold well at all, more like a loose sheet.

 

[skunkiebeer]

I hope everyone’s right!!!
Definitely gonna keep an eye on it.
I’ve had this color in my tank for about a year and just recently started spreading. Does cyano spread really quick?

 

[WheatToast]

Is this dark purple stuff Cyano or Coralline? It’s not hairy and doesn’t come off when I scrape it with my finger nail. My tank is over 2 years old and this stuff doesn’t look like my lighter colored coralline. I’ve never dealt with Cyano so I’m kind of panicking. It’s on some of my live rocks but not on the sand bed.View attachment 2627514

It’s neither Coralline nor Cyanobacteria. My guess would be Peyssonnelia or a similar, benign red encrusting macroalgae, which are often incorrectly referred to as “Red Coralline” (in my opinion, they contrast beautifully against lighter colored Coralline). You might want to remove those Asterina starfish, though.

 

[skunkiebeer]

It’s neither Coralline nor Cyanobacteria. My guess would be Peyssonnelia or a similar, benign red encrusting macroalgae, which are often incorrectly referred to as “Red Coralline” (in my opinion, they contrast well against lighter colored Coralline). You might want to remove those Asterina starfish, though.
View attachment 2627540

Lol yea I pluck them out here and there. So this stuff isn’t harmful?

 

[WheatToast]

So this stuff isn’t harmful?

Yup! Harmless and slow growing.