Whats going on with my zoas?

[dmward1457]

So, this colony of Zoas is over a year old and was much denser than these images at one . About 2 weeks ago, these translucent, reflective "bubbles" appeared in the middle of them and in the last few days, the center of the colony has disappeared. The "bubbles" are firm to the touch and can be found on rock in other areas of the tank. Not sure, but I do not think it to be pox based on what I've read and seen. They almost appear as if they were placed there. I have a fire shrimp, several other zoa colonies (which are not having a problem), several Duncans, several varieties of snails, sand sifting star, a couple clown fish and a blue tuxedo urchin. Coincidentally, many of the "bubbles" appear to have a blue marking similar to the blue tuxedo. I have seen it spawn but have not been able to find any information about eggs, etc? This colony sits about mid tank and gets moderate flow. Everything else seems okay. Any ideas? 

[JohnMzreef]

valonia?

[BearTheSquare]

Looks a lot like Valonia (bubble algae) to me. Here’s an article on how to remove it and keep it out. If it’s early stages it shouldn’t be too hard to deal with just, manual removal.

https://pets.thenest.com/cures-bubble-algae-saltwater-aquarium-12510.html

[dmward1457]

Looks and sounds like it. Most of the methods for removing it seems pretty invasive. 

[mcarroll]

What are your nitrate phosphate and alkalinity levels currently?

 

How old is this tank?

 

What fish do you have and for how long?

 

Depending on your answers, either doing nothing (except perhaps increasing your cleanup crew) or manual removal seems like the best option. (There is more than one species of bubble algae, by the way.) 

 

Manual removal does carry a slightly increased risk of spreading the algae compared to doing nothing, so if conditions are good doing nothing can definitely be a better option.  

 

Personally, FYI, I have never had to do anything versus bubble algae when it shows up and it always goes away on its own. It also never spreads very far in my system, I grow a ton of stony coral, I have very few fish and low feeding rates to match, but I also filter the tank very little… Almost not at all.   My tank does grow hair algae and other forms of algae as well and I have a well matched cleanup crew of a few hermit crabs and a lot of snails.  

 

Oh, bubble algae is also by far the best looking algae you'll see. I have a German aquarium manual from the 1990s that calls it the jewel of the reef.