hello, i picked up 3 of these little guys from a lfs they said they'd grow about 6-8" and be fine with a pictus. they are about 2inch and they were £4 each...sorry for the pics they are in a 55 now but will go into a 120 when bigger.
With synodontis cats, the juvenile markings look very different from the adult form.
They are great catfish. They are not fussy eaters...they'll take prepared foods as well as frozen (bloodworms, brine shrimp, etc.). They do like a lot of cover, wether it's plants or driftwood. If they are indeed robertsi, they max out around 4" or so.