A lampeye needs some help.

[Erica Stolte]

How large is the tank? 20 gal.
What are the inhabitants of the tank? 10 lampeyes.
How long has the tank been setup? Probably at least a year.
How long has the fish in question been in the tank?   Since last Sunday.
How long has the fish been exhibiting the symptoms Every since I put them into the tank.
What type of filtration is being used on the tank?  A whisper internal filter and a fluval 2 internal.

Ok, so I got these Lampeyes ( procatus simus) On Sunday and when I put them into a tank, I found one was wounded when I released them into the tank. Like a notch injury in the back. Lines up with the ventrals fins on the bottom. I'm afraid this might have happened due to how slow I was about putting them into a tank. I took a nap when I got home and I ran an errand.

I am aware they need a larger tank and I made the choice to put them into the smaller tank because it was a established. 
I do have a larger tank they can go into later. ( there's a bit of a story about why I didn't end up getting this tank setup before I went to the killie event).
About the injured one, I'm getting concerned as the wound is not improving/healing. For now I had decided to leave the injured one with the group as they were quite frightened at first.
What should I  try and do next with the injured lampeye?.

I do have a five 5 gal sick tank I could use.

[Erica Stolte]

Never mind, I found the injured one dead today on the bottom of the tank.

[Ppulcher]

That's too bad.  Sometimes fish just don't travel well, particularly if they've picked up an injury somewhere.  Those Procatopus are gorgeous fish.  Enjoy the remainder of the school!