Help id'ing round things in aquarium?

[fireflies]

So I made a post yesterday about my molly who had a round thing on his mouth, and a few people thought it could maybe be a foreign body. I was unsure at first as I couldn't think of anything like that in the aquarium, however I have just come across these on the thermometer which looks very similar! Any ideas what they are, they look a bit like eggs? I can't see any others in other parts of the tank, but there's two large pieces of wood and various plants, so I can't be sure there aren't more somewhere.

These are the fish currently in the tank:
6x congo tetras
4x mollys
2x swordtails
6x corys
1x nerite snail

 

[MaloK]

If they're soft I would say cory eggs, if they are hard and difficult to scrape, nerite eggs.

 

[Colin_T]

They look like fish eggs, probably Corydoras.

Congo tetras scatter small eggs among plants.
Swordtails and mollies give birth to live young.
Corydoras lay groups of eggs on hard surfaces.
Nerite snails produce different shaped eggs to round balls.

 

[Sparx]

Makes sense if that was an egg stuck to your molly’s mouth, he probably tried to eat it and it just got stuck to his lip

 

[fireflies]

I've never seen the corys lay eggs before so that's exciting! They've only been in this new tank about 3-4 weeks so it's good to know they've settled in well

@Sparx Yep haha, eyes bigger than his stomach I reckon Looks exactly the same so I'm betting it was an egg!