concerned, please tell me what these are

i just found these for the first time this morning in my tank. they came overnight. they are little white puffy circles on the rock. At first i was thinking they were some sort of flatworm so i took tweezers and grabbed one. It popped and released some material into the water. Where it had burst was just bare rock underneath it. I did just get my cuc from reef cleaners the other day, so i am thinking these are egg sacks from one of the species of snail he sent me. Are these bad?

 

I'm curious myself, I get these around my tank too but never has made any harm...I wouldn't worry.

 

lou, may have the answer. Look up nerite snail eggs. This seems to be what they are. Makes sense because i just got some nerites a few days ago from reefcleaners.

 

I'm not sure either. They're not as uniform in size as snail eggs.....

 

Nerite snail eggs

 

thanks 2in10. this is something i have not seen before. Im relieved it turned out to be harmless.

 

I tend to agree. They are easier to tell when they lay them on the glass, as they are yellow in the center on the other side

 

Harmless is correct also highly unlikely to see anything come from them too. We do not offer the right environment in our tanks for a successful hatch. I think a brackish environment is needed IIRC.