Upside down catfish usually refers to Synodontis nigriventris, which prefers to be kept in small groups (say 5+). Also, depending on what kind of africans you keep they may just bully him back to his hiding spot. While some synos like S. multipunctatus can hold their own against the toughest cichlids, S. nigriventris is a peaceful shoaler and may be overwhelmed by aggressive tankmates.
very good info.. he may be the wrong synodontis for your african cichlid tank.. and also even the ones that can hold their own often hide when they are this small.. my concern with yours is whether he is getting enough to eat. if possible i would slip some food such as blood worms into his cave until you decide to move him.. they need to eat AT THIS size a regular diet.. if possible grow him up in a small tank and once he is larger and healthy try him again in the tank with the cichlids