I was actually looking into a way to sex catfish a while back.
seems you can get an home ultrasound kit for around $4,000. Plugs right into your laptop or desktop computer. Might even be an app for iphone by now lol. So yeah, apparently this is a really good way to sex catfish and some of the hatcheries have started using them as well now that the price is dropping. Exploratory surgery use to be used as well. Catfish(most species) have very little sexual dimorphism. Very extremely hard to sex non the less. Good luck.
Just remember that even females will become slimmer if they go on a food strike. This skinny vs. fat method is mainly used when the female becomes full of eggs, and you'd need to keep them under ideal conditions for spawning for that to occur. Some species of catfish would require recreating seasonal changes that occur naturally in the wild to get the occyte developement to even happen.
I'd love to see someone spawn some ecats!!!!
