Dave,

Bill Cody can tell you more about the round cages, and I believe to make round cages you use water line material that has a tendency to round it self out and just connect the ends.

I prefer the square cages because they are easier to clean algae buildup off for me. I stand on the pier and vigorously brush up and down the side of the cage on the inside and then the outside, and then rotate the cage to get the next side and so forth. I also allow the cage to float over a diffuser to break up algae build up on the bottom of the cage while I am cleaning. In my fertile pond I sometimes have to do this once weekly and don't think it would be as easy with a round cage.
But I could be wrong.

I also make cages up to 10 feet in diameter which may have some bearing on shape of the cages. I do not have any problems with fish bunching up in the corners and no visible damage on the surface of the fish. However, I may be growing the densities others are. I have about 100 bass in a 7 X 7 X 4 cage which comes out to about 200 cubic feet. My bass are getting close to release at about 9 to 11 inches. I have bass in three cages right now and bluegills in another.

I don't feed the morning preceding cage cleaning to reduce stress. What amazes me is how well bass grow and handle living in cages. They seem to be resilent to the stress of cleaning too as they will feed normally that same evening after a day of cleaning the cages.

What I believe really helps me with the success of my cage culture is I have a diffuser on the bottom between two cages on one side of the pier and between another two on the other side of the pier. I have then set up so the diffuser not only pushs water to each cage on each side of the diffuser, but the flow also goes sideways to the other side of the pier into one of the other cages. I would not advise putting a diffuser right under the cages permanently as too much flow stresses bass and bluegills. It would probably be just fine for trout though.

Actually my bluegill cage is farther away from the flow then the bass cages as they are a more sendentary fish.

If any of you would want to try feed training, attempting it in a cage is an option if you crowd them enough and they are small enough in size.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.