Population explosion. Please ID snails.

[Troy V]

These have been in my system for years. But I noticed in the last 7 months when I turned my skimmer off the population exploded. They seem to love nutrient rich water. I only see them on the glass eating algae with their mouths. The look like Nassarius snails but these are never in the sand bed. Rather they gather on the glass to feed at night and lay eggs. Any given night you will see at least 100 on the front glass. I can't get a close-up of the mouth, but it cleans the glass with a similar mouth structure as any other algae eating snail.

Here are 3 egg sacs. Each one housing many tiny eggs.

Here are 2 of them doing the deed, and making new egg sacs.

 

[flagg37]

Their number and behavior sounds like cerith snails but they’re usually black and look smaller. You’re right that they look like small nassarious snails though.

 

[taricha]

I have some also. These are sometimes sold as "mini strombus" such as from Indo Pacific Sea Farms.
however, they are identified as collumbellid snails here: http://www.reefkeeping.com/issues/2004-07/rs/index.php
great herbivores that eat epiphytic growth off of macroalgae, rocks etc.

 

[ahiggins]

look into different whelks as well. that shell shape has me a little worried.

 

[KJ]

Here are 3 egg sacs. Each one housing many tiny eggs.

Collumbellid snails eggs

 

[KJ]

It is a

These have been in my system for years. But I noticed in the last 7 months when I turned my skimmer off the population exploded. They seem to love nutrient rich water. I only see them on the glass eating algae with their mouths. The look like Nassarius snails but these are never in the sand bed. Rather they gather on the glass to feed at night and lay eggs. Any given night you will see at least 100 on the front glass. I can't get a close-up of the mouth, but it cleans the glass with a similar mouth structure as any other algae eating snail.

Here are 3 egg sacs. Each one housing many tiny eggs.

Here are 2 of them doing the deed, and making new egg sacs.

It is a Collumbellid snail .

 

[Troy V]

Thank you everyone. You guys are the best!

The way they stay on the glass and eat algae. I believe they are Collunbellid snails. I have never seen them in the sand bed, or become more active during feeding times like I've seen Nassarius or Whelks.