Cory disease not sure what it is

What are your parameters?

Huh? I’m new to fish keeping so could you explain what that is to me please?

Get yourself a API master test kit. Its your best friend.
You could also go to local fish store and they can test it for you.
You need to test for
gh, kh, ph, nitriate, nitrite, ammonia.

This is VERY important.

Have you cycled your tank?

What is your tank stocked with? How big is the tank? How long has it been set up for?

My tank is a 510 it’s been set up for about 4 months it has real plants, gravel, a circular hidy hole and a log. Here is some photos of it.

maybe the angelfish are bullying it

Hi and welcome to the forum

Can you post some clear pictures of the fish and tell us what the problem is?

How often do you do water changes and how much do you change?
Do you gravel clean the substrate when you do a water change?
Do you dechlorinate the new water before adding it to the aquarium?

What sort of filter is on the tank?
How often and how do you clean the filter?

How often do you feed the fish?
What other fish are in the tank?

Have you added anything to the tank in the 2 weeks before this started?