As to recommending fish, it's always difficult, partly because what I think is a "Nice fish", someone else thinks isn't so nice (for whatever subjective reasons). Catfish that is constantly active are pretty rare. There is Corydoras, but they are relatively small (but a LARGE shoal of Corydoras in a large tank would look stunning). Some of the Pimelodidae can be quite active and outgoing, but my experience is that they tend to hide if they are not hungry (or there is no food available).
welcome along! nice to see new members! in my experience a pimelodus pictus would be a good fit for an active cat! i had a single one and he was as active as any fish! so i can`t imagine how active a group might be! so if you picked up a group you could have a lively tank! and the best thing is that they are a very avalible and cheap fish!
"Fishing provides that connection with the whole living world. It gives you the opportunity of being totally immersed, turning back into yourself in a good way. A form of meditation, some form of communion with levels of yourself that are deeper than the ordinary self."
I second the S. brichardi suggestion, and would add Synodontis decora to the list of "social Synos". They can be a little hard to find, and there are hybrids about, which means there may be fish that looks similar to S. decora but aren't "right". Stripey tail and dorsal fin extension are the signs to look for.
November, it may be wise to choose several species you'd like from the Cat-elog and put them in this thread or rather start a new one. By doing so other members may be able to help you out in a better way, as there is quite some choice and only you know what you'd really like to keep. Also, people don't expect your current question in an introduction topic, so there won't be many replies.
Possible title of that new thread: help me find a shoaling and visible catfish (or some such).