Silver-tipped Shark Catfish (Is he sick!?)

[Waterthoughts]

UPDATE-
all in all what happen was:
my cat fish were fine. my Gouramis died from amonia poisening which was really sad. after that i had the two cat fish in there for about a month doing just fine. seemed happy. then recently i got a 20 gl. and moved them into that. they were happy untill my tank got infested with ich after adding two new fish. my silver tailed catfish died from stress and the ich i assume. and now my other cat fish is hiding somewhere i cant find him.
basically, i 've learned alot, and know what i gotta do in the future. i think my fish now will be alright.
thats pretty much the story.

 

[blurock]

I am sorry about your loss. I lost my 6" Columbia Cat then replaced him with a 3" who I tried to keep in a 5gallon. Although at that size they should technically work in a small tank for awhile, mine died very soon in the smaller tank, I just don't believe they enough space as they are so active. After I lost that one, I have gotten two 2.5" Columbians and have them in a 20 gallon, though they will need a larger tank as they reach adult hood. If you were going to try them again, I wouldn't put a juvenile csc in anything less than 20 gallons, and make sure you are going to be able to upgrade to a larger tank when they grow. Also make sure your tank is heated (around 80F). Another general good idea for keeping any freshwater aquarium fish is adding a small amount of aquarium salt to your tank (1tsp for every 5g).
Don't feel too bad though, Columbian cat's are the only fish I have ever had issues keeping. Oh and about the "scratch" on it's head. All my csc's have had what looks like a scratch or scrape on their forehead, and I'm pretty sure its just the shape of their skull and their thin skin over their head, or coloration or something. I know Red Devil has two large csc's and they have the same spot, just larger. You can see pics here http://www.monsterfishkeepers.com/forums/showthread.php?t=125978

Don't give up in your fish keeping, it takes practice, time, and a lot of research. If you want to know more about different kinds of Catfish you could go to PlanetCatfish.com and find a species that may work better for set up. Columbian Shark Cats can get to be about a foot long, so if you are not able to get a bigger tank I would just look at getting a different species, maybe look into some Synodontis that don't get as large.
Good luck, and keep us updated