flourescent green egg?

I just noticed this flourescent green bubble or egg of some sort on one of my rocks. I have tried taking pictures but my camera is terrible. It is really small, about 3mm in diameter and there might be like 2 or three of them. I suspect that it is some sort of algae(not bubble algae) or eggs. I remember reading something about a green isopod egg awhile back but i don't remember for sure. I am not really worried about it, I'm just curious about it. Anybody got any ideas?

 

I was going to say bubble algae but i guess not so I'm not sure.

what kind of fish do you have in your tank?

 

I don't have any pairs of fish.

 

are you sure it's not bubble algae i did a quick google search and found that there are more than one type of it



Valonia macrophysa - smaller clustered elongated bubbles
Boergesenia - clustered, though less dense in numbers and elongated bubble shapes
Ventricaria ventricosa - can get quite large (around and inch) and grows in clusters and in singles
Dictosphaeria ocellata - usually smaller grouping slimey looking bubbles, can be a lighter shade of green
Dictosphaeria cavernosa - encrusting like growth forms with pitted looking bubbles

 

Yea i am sure. I have had experience with 4-5 types of bubble algae and I have never seen anything like this in any of my tanks or come across this doing research. I feel like i should be an expert in bubble algae by now because I have dealt with it so many times.

 

Could be a sponge if you are sure that its not bubble algae. Is it lime green? I have some like that in mine.