Your husband did buy an iridescent shark which happens to be a type of catfish.
I owned one of these once, it died during the 2 week power outage following Hurricane Sandy along with every other fish in the tank EXCEPT my common pleco.
I had a 60 gallon tank that the shark, at 13", could just barely turn around. In addition, iridescent sharks get spooked very easily with age and will torpedo back and forth across the tank and smash into the glass. This caused many injuries and a host of infections over the years I cared for it.
The life of an iridescent shark in the home aquarium is more often than not a sad one. This is one fish that I will never own again.
Having kept one of these for 8 years, I strongly recommend returning this fish to the store.