I actually own one! BELIEVE IT OR NOT. I felt compelled to 'save him' from the LFS as he has a 'nemo' fin (short n' stubby...genetic I believe...as it's never grown back). I purchased him at about a 2" size...and remember, I was fully committed to seeing this through, to the end (as he walks to Mordor to destroy the ring...this is how epic this fish is, F'n MORDOR...FIRE, GOLLUM...WHOLE 9). Growth rate wise you can expect your cat to hit about 6" within 4 months...then usually a foot within 9-12 month range, he will need moved from your 40 within the year most likely. They have insatiable appetites, mine usually inhales my finger during feeding (no teeth, not an issue). I would not recommend 'under feeding' to dwarf their growth rate however. Also, you need to watch in smaller tanks that their trademark shovel nose doesn't bend 'downward', this is a trait of a severely cramped fish and can lead to other serious problems. They are amazing beasts, with the growth and overall personality...it took mine a while to warm up, frequently he would get skittish and sprint about the tank, knocking things over, etc. (Steeler season is rough on the fish in the living room...we take football real serious 'roun here). They are best kept on sand due to their propensity to INHALE food, although at bigger sizes passing gravel is a walk in the park. Feeding wise I feed him carnivore pellets of decent size, earth worms usually every other day, feeder fish when the kribs get too "frisky" or whatever else. A varied diet seems to work best IMHO. For a smaller, manageable catfish, I would also recommend a lima shovelnose. They are wonderful fish, and hit about 4 foot as adults...maybe even bigger. It's a heated debate in terms of what size tank is needed to house them to adulthood, so I won't even go there. If you are anything like me (and hopefully the rest of the members here), I can't stand to see my fish cramped or unhappy/unnatural and will take every effort to improve their quality of life (be that with a bigger tank, or offering them for sale/donation in order to see them through).