Ramshorn Snail Experts Needed

[GardenStateGoldfish]

Hello All! 

I have noticed on one of my high particulate tanks (minimal filtration) 270 gallon goldfish tanks my rams horns all have this side hole open but it isn't something I have really seen in the other tanks. It got me curious, do they/can they filter feed with this hole? or is it just a coincidence. I noticed pretty much all of them in the 270 doing this (that I could see) as they moved along the glass eating. I know for mystery snails its a breathing tub but that does not appear to be the case for the rams. 

Thanks! Disclaimer, not my photo, I was going to try and take one but I found one online that already had an arrow to the hole I was talking about. 

[H.K.Luterman]

Ramshorn snails aren't capable of filter feeding, or feeding through any opening that isn't their mouth. I can't find a definite answer to what that opening is, but it's mostly likely either the sheath to it's sex organs or it's poop chute. X3 

[GardenStateGoldfish]

Thanks, I figured as much but I was just curious since it seemed to be happening in the tank I was getting ready to try clams in (high particulates) but not in the other tanks. So It was more wishful thinking on my part that they were filter feeding lol.