you could keep raphael, but I dont think that oscar could go in there too, oscar would need at least 60 g for single fish alone.
here some treads I posted before and other people's thread,
http://www.monsterfishkeepers.com/forums/showthread.php?t=303443
http://www.monsterfishkeepers.com/forums/showthread.php?t=292776
http://www.monsterfishkeepers.com/forums/showthread.php?t=297821
you could find more on raphael catfish on the catfish forum, or just use the search bottom on the left window.
I used to think that raphael is boring to keep, but the way I set up their hiding place, and the number of them that I got makes it more interesting keeping them in my tank,
you could do something similar if you want to or maybe set up a better home for them, but the more they hide then the more you find them boring.
If you let them, they will hide all day long and you could never see them, they only active when the lights are out. So I would say its all depending on the tank set up and the number of them cause they also do well in groups.
They are easy fish to take care off, and they'll accept anything they could fit in their mouth. So if there are other tank mates small enough to be their meals then dont be surprise if those tankmates are gone one day.
There are other types of raphael catfish which is the spotted raphael but doesnt grow as big as the stripped raphael could get.
All Raphael catfish grow very slow, so be patient with them.