I have owned one Rusty Jello but only for a little over 14 years.
Bought at 17.8cm total length on January 3, 1989. Bought at Big Al's Aquarium Service original store on Dundas St in Mississauga Ontario Canada for $30.00. Kept in a 680 litre by itself till the summer of 1995. It was known then as Pseudopimelodus fowleri. (Haseman 1911)
Measured at 63.5cm tl at that time and moved into the 196kl (1097 cm long x 823cm wide x 275 cm deep) L shaped.
Ate well and lived in a cave among the 120cm high rock piled around the walls of the tank. It did have a favourite cave located near the 120cm dividing
wall and appeared anytime the tank was being fed large chunks of fish. The only aggressive time I noticed was when it tried to eat a young 45cm tl Phractocephalus hemioliopterus as it was added to the tank in September of 2000. The red tail swam to the bottom of the tank when it was introduced and close to a cave the fowleri was in. this would be at a depth of between 240cm and 275cm
It never bothered much larger P. hemioliopterus.
It was an ambush predator in my tank feasting on the large number of african cichlids swimming among the rock piles.
It died nov 12, 2003.