Well having kept paddlefish "dinks" supposed to be genetic dwarfs that crop up from time to time, after 3 years of keeping them I can honestly say they are very interesting and for those who want to invest in a really large aquarium, 225 or larger, custom build is better because you need a bigger tank footprint than you need tall for swimming room.
Mine did quite well, feeding on floating pellets at night and small feeder guppies during the day. Mine never got more than 10" long even though they eventually graduated to a 300 gallon vat. I started them out12 or so of them at 3" long in a 30 L and as they grew I transferred them to a 75 and then to the 300 gallon vat.
The vat was where I saw some of the more interesting behaviors, they managed to scoop up live ghost shrimp and tiny crayfish from the bottom but when I added several dozen feeder guppies was when the fun began. The paddlefish would swim after them and eventually get them all together at the center of the vat in a "bait ball" and lung into them to scoop them up. Sadly it would seem that dinks only live about 3 years or so according to my sources but they were a lot of fun and did eventually come to recognise me as the food giver and would get excited when i walked into the room.
I would like to repeat that you need a really big tank to keep them in and it helps to start them out in a small tank so you can keep track of how much they are eating.
If I ever set up a really big sturgeon tank (which is my goal) one of the fish to be included will be a paddlefish...