Congratulations sailornight6.
They are great, aren't they?
Yes, get at least 3 more of the same species. They are scavengers but they don't eat garbage. They are omnivores so feeding them a diet of algae wafers is not a good thing. Get them sinking tables that have protein in them like Nutrafin Max Sinking Tablets, Sera viformo food tablets, Hikari Sinking Wafers. You should also supplement with live or frozen food like brine shrimp, blood worms, black works, etc. A varied diet is the best (mine get all of the above). Once a week I give some of them sera vipachips although my C. atropersonatus don't seem to care for it. But the frozen food? Oh ya!!!
After feeding them give them about 1/2 an hour to finish eating. If there is food left over after that and they don't seem interested anymore, siphon it out otherwise your tank will foul pretty quickly.
Beach or river sand is the best. I've tried silica sand in one tank but it appears to have worn down their barbels so that's getting changed to beach sand. I've also had luck with using smooth pea gravel. I find that gravel is the easiest to keep clean as I vacuum it weekly when I do my 25% water changes (very, very important). Sand is harder to vacuum. Well, actually it's easy to vacuum but you also vacuum up the sand...
Give them a place to hide, either under some wood, some dense foliage or a flower pot.
Check out the library or bookstore for books on them and search the Internet for more information on your specific species. This forum and Google is your friend.
Good luck and cheers.