ID please

[Jeremy_d]

I have this blue stuff that is kinda clear but a very bright blue on parts of my live rock. I’ve seen it in 3 places. Doesn’t look like a sponge to me and doesn’t seem like a tunicate either as it’s not growing and as far as I can tell it’s not pushing water out. rock is from a tank that is about 15 years old as well as a few pieces of rubble from the ocean. The spot photographed is 3/4” long

 

[tzabor10]

Lavender sponge
Picture by Tampa Bay Saltwater

 

[Jeremy_d]

Lavender sponge
Picture by Tampa Bay Saltwater

I’ll have to keep an eye on it, I’m not confident that it is a lavender sponge but if it gets larger and less transparent I certainly appreciate the insight!

 

[beamers]

Following along until we get a positive Id. I’ve had something similar in the past but it either died off or was eaten.

 

[Formulator]

What is the texture like? Is it slime or encrusted to the rock? Though rare, I think some cyanobacteria can be that color.

 

[Jeremy_d]

What is the texture like? Is it slime or encrusted to the rock? Though rare, I think some cyanobacteria can be that color.

I tend not to touch things I’m unsure of haha. I have some love rock and rubble in the substrate from the Bahamas so I’m thinking it could be something wild

 

[ISpeakForTheSeas]

I have this blue stuff that is kinda clear but a very bright blue on parts of my live rock. I’ve seen it in 3 places. Doesn’t look like a sponge to me and doesn’t seem like a tunicate either as it’s not growing and as far as I can tell it’s not pushing water out. rock is from a tank that is about 15 years old as well as a few pieces of rubble from the ocean. The spot photographed is 3/4” long

I'd actually be kind of surprised if this isn't a sponge - you would be hard-pressed to see even large sponges moving water without some sort of reef-safe dye to show you the water flow; on a small specimen like this, I'm not sure if you would realistically see much movement at all even with a dye.

Regardless, keep an eye on it, and if it grows, get some more pics for us to see.