My bad I didn't clarify when I say I wouldn't risk it on down I am talking about the syndontis and palmas palmas.I personally have not tried them with raphael catfish but with these guys tank mates as long as no one is a threat to the other they usually get along just fine. I personally wouldn't risk it, but since it's an UJ it could work out as long as it is kept well fed. UJ IME usually don't eat other tank mates it's usually the LJ and not just LJ but really hungry LJs. IMO if you keep him well fed you shouldn't have any problems, but you will always have to know with that size comparison there is always the chance as long as they are in the same tank.
My bad I didn't clarify when I say I wouldn't risk it on down I am talking about the syndontis and palmas palmas.
How big does a fish have to be before the palmas palmas cant eat them?They should be ok but there will always be that chance. However with UJ they tend to not eat tank mates unless they are very small and if the poly is hungry. So I would definitely put the larger one in there first to let the poly get used to it and see if there are any problems. If there aren't then I would out the smaller ones in there. I would still watch carefully between them and make sure to keep the palmas palmas well fed.