I never see my upside down catfish hardly at all. I saw him the other day just briefly after a feeding but I can't even figure out where he is.
Which species of Synodontis is it? S. nigriventris is the most commonly labelled "UD Catfish", but it's also a common name for Syno's in general. S. nigriventris is a small, schooling species, and don't really appreciate being kept as singles or pairs.