These really adorable little catfish (there are actually many species and colorations besides the one shown, but they are pretty much all the same in behavior) will snuggle into the hearts of anyone who ever tries owning one.
They are small and never exceed an 2 or 3 inches, and never bother a soul. All they do is swim around diligently all day long, looking for worms and uneaten food scraps in the substrate. Care should be taken that whatever gravel or substrate you use, it should not have sharp edges; this will cut their delicate short whiskers. They love to swim in small groups of 3 or more individuals, and will cuddle up to one another while searching for food. They do not need a ton of food either, but don't make the mistake that some do and think they will live on detritus only.
Like any fish, they need nutrition, and probably can't live on scraps other fish leave behind, unless the tank is very sparse and doesn't have many other fish in it. In general, supplementing a tank with a small group of corys involves dropping in a tablet food (algae wafer or other bottom feeder solid fish food) once a week. Don't feed tablets daily, as this will likely result in pollution. When you do drop them in, drop them in at night, when the other fish are asleep; they corys can still find it, because they hunt mostly by tasting with their whiskers. They also love treats of frozen bloodworms and brine shrimp, dropped in once a month.
There are a few minor things that people should be aware of with them; they have small barbs on the sides of their gill flaps for defense, and these sometimes get caught in nets. Also, they have a neat habit--they are able to absorb air directly through their intestine, so if you see one suddenly dart up to the surface and suck in a bubble, and then go back down, don't be too alarmed. They are compatible with just about any fish I could think of, save ones that might try to attack these peaceful little guys that always try to mind their own business.