What is going on?

[KatB87]

I came back home from being gone for a few days and my fish looks like this.
I have eight other fish in the tank all goldfish and smaller than this guy. I dont know if he tried to swim unsuccessfully through a hole in the decor of the tank or if its some sort of illness. None of the other fish have any marks on them like this or otherwise. Any help and input is greatly appreciated.

 

[WendiDell]

He does look a little beat up. But more info is required. The pictures help but more is needed.
What size is your tank? What are your water parameters, Ammonia, NitrItes, NitrAtes, pH? When was your last PWC? Have you added anything new to your tank? Or changed anything at all before you left? Did you have someone taking care of them while you were gone? Maybe they did something different?
I'm probably missing a few questions, but that's a place to start.

 

[Crypto]

I agree.

We are going to need your tank parameters (nitrite, nitrate and ammonia)?
When was the last time you have done a water change?
What are the tank mates?
How long has it been set up?
Did you cycle it?
How big is the tank?

 

[WendiDell]

I agree.

We are going to need your tank parameters (nitrite, nitrate and ammonia)?
When was the last time you have done a water change?
What are the tank mates?
How long has it been set up?
Did you cycle it?
How big is the tank?

I knew I was forgetting a couple of important questions, thank you.
(except the tank size, that was my first question)

 

[Hubert90]

Looks like an ulcer. Hmm Ur tank looks way overstock. Like the others. Let us know Ur water parameters and tank size.