What is this

[OneWhoPokesBears]

So I just noticed this today. Looks like a light blueish film. Tried to take the best iPhone pics I could. Any ideas?

 

[DSC reef]

Looks like sponge. How long did it take to grow?

 

[ReefEco]

Yeah, kind of looks like sponge, but I'm guessing not if you just noticed it (unless it was at the back of the tank or on a new rock you just got?) That amount of sponge would take a long time to grow, and they are usually not in sheets like that. Odd.

 

[Fishhands]

Hard to tell wih blue lights, but blue cyano?

 

[Tyler_Fishman]

It's Definietly cyano

 

[LbulletM]

I'm voting cyano or some sort of bacterial bloom. Can you get a picture with whites?

 

[DSC reef]

I agree, it looks bacterial. Especially if it appeared over night.

 

[Scorpius]

Sponges.

 

[Hans-Werner]

Hard to tell with this blue light but I think it is some kind of bacteria too. If there is a lot of rotting in the rock it could be Beggiatoa, a white sulfur bacterium that looks like mold. Since I think you have not introduced fresh live rock with a lot of rotting sponges and algae it most likely is cyanobacteria (Oscillatoria).