Little snail like critters appeared on rock

[Qasim]

Hello for the past few days under UV light or night time we can say little critter have started to appeare on rocks as on the pictures below. They are not seen during day time might be hiding within the rocks but the look like little tiny snails. I have like 5-6 snails looking adult but I dont if they are adults or not. The little ones have covered a amount of rock surface hopefully they are next gen cuc in my tank

Sorry for the photos dont show up clearly one have to zoom in to see the critters

Thanks

 

[Tahoe61]

Collonista, harmless film algae eaters.

 

[Greybeard]

I concur on the ID

Under the right conditions, they can breed to nuisance levels, clog up pumps and powerheads. Usually doesn't last, they seem to die off after a while.

 

[Qasim]

Here are better photos showing them under nirmal light