Hi Jake
I think you need more than a store (lfs=local fish store). Petland Discounts is not the greatest place to get started in the hobby, but they do have the best prices going on 55 gallon tanks with stands, and they do sell live blackworms. File those two facts away for future reference because once you really get going with this, you may find them useful.
I've looked through your posts and your blog, and am not sure you know how the bacteria thing works. In short, you have to cultivate what we call "beneficial bacteria" to convert the ammonia in your fish's waste products to the more safe nitrAte. If the tank is done right, there will be a balance between the fish in the tank and the amount of beneficial bacteria in the filter and on the other surfaces. Let me explain how this works.
There are some bacteria in a "cycled" tank that consumes Ammonia, which is poison. When they do this, they convert it to NitrIte, which is also poison. That's not as bad as it sounds though, because here is another kind of beneficial bacteria that eats NitrIte and converts it into NitrAte, which is not harmful in small amounts. The NitrAte can then be removed when you do your weekly water changes.
When you do your water changes and tank cleanings, you must add dechlorinator to the water to remove the chlorine that the water dept. adds to kill bacteria. If you don't, or if you rinse your filter media in tap water, it will kill the beneficial bacteria you've been trying to cultivate. If you've done that, and the tank is just a few weeks old, I suspect your tank isn't cycled. If this is the case you have a major problem here and will need to do something fast to prevent your fish from dying horrible deaths.
The quickest way to get a cycled tank is to add filter media from another tank that is cycled. If you have a friend who has some, and will share it, you could just add it to your filter. Or, there's Bio Spira, which is the only live bacteria product you can buy. A good lfs will keep it under refrigeration. Don't let them sell you anything else; it won't work
OK, the catfish you have there is a cory cat of some species, but I can't make out which one. They are peaceful fish, but they live in schools. You could keep 6 or maybe even 7 of them in a 10 gallon tank, provided there were no other fish in there too. In my opinion, cory cats are the best thing going!