Goldfish strange upper lip. Disease?

[Goldfishkeeper]

Hello. I recently noticed that my big white goldfish has a strange looking upper lip. I can't figure out what it is by searching the internet. I would love some advice. I understand about quarantine tanks etc. I've had this fish with his tank mates for a while now. It seems to be intermittent. I only notice it when I feed the fish lately. He extends his lips out and it looks like extra skin covers his mouth. He can still eat and play in the sand. Other times he looks completely normal. I took some pictures. His lip doesn't look fuzzy or cotton like at all.
Thank you.

 

[Colin_T]

Hi and welcome to the forum

It's normal for a lot of fish to be able to extend their mouth out a bit. It helps them engulf food. When they extend their mouth, a thin layer of skin holds the bone and mouth together. Your other fish will have it too but it will be a different colour if they aren't white. It's normal and nothing to worry about.

 

[Goldfishkeeper]

Thank you very much for letting me know! I'm glad he's OK! He's our biggest fish, so maybe it's easier to see it on him vs the others. Thank you!