Orange patterns on glass

[Salty Rambler]

Any thoughts on what this orange substance growing on my glass might be? It can be removed with a blade, but continues to grow back. The growth pattern reminds me of a fingerprint...

 

[HudsonReefer2.0]

Algae. Scrape grow scrape. Sign of a healthy tank

 

[Asm481]

Algae that is being grazed on by one of your fish?

 

[Salty Rambler]

Algae that is being grazed on by one of your fish?

That was my first thought, but the pattern is too widespread and consistent to be fish or snails, and I haven't seen them clearing any of it.

 

[Cell]

Algae eaten by snails.

 

[Salty Rambler]

Algae eaten by snails.

Can algae be orange? The color is off in the picture, but it is definitely orange. The pattern is throughout the whole tank vice a path.

 

[Murica]

Can algae be orange? The color is off in the picture, but it is definitely orange. The pattern is throughout the whole tank vice a path

yes it can. It can also just be a light brown. I constantly have that in my tank, it’s algae being eaten by snails and my kole tang

 

[Cell]

Orangish/light brown sure.

 

[OrionN]

That is algae eaten by one of your larger snails. Teeth marks. You can look at the next time a snail craw on the glass.