I'd rethink the fish truck option.
Your supplier buys their fish from the same sources as the fish trucks.
For the risk of bagging fish, compared to the risk of rigging up a way to use welding oxygen, I'd also rethink what their delivery charge would be, should you choose to try to haul them. To rig up oxygen, you'll need containers, flowmeters for each container, a regulator for the oxygen bottle, and splitters to go to each flow meter (or a valve for each container, should you choose that route.) If you buy the regulator and all the rigging, you'll be around $300, not counting diffuser hoses and their connections. To set up a rig to haul 4 different types of fish, that's a sizable investment.
Another idea is to use 48 quart coolers with Aquarium air pumps and air stones. With 120 volt converters in lots of today's vehicles, that might be a better choice. You could haul the minnows at two pounds per bag, kept cool, and they'll do fine. Then you need to rig up for the catfish, hybrid sunfish, and hybrid stripers. If you have two coolers, put the catfish in one, sunfish and hybrid stripers in another, and bag your minnows. One other thing about bagging the minnows. Put each bag into a five gallon bucket. That way, if they spring a leak, you don't have a mess.
