I am guessing 3 feet across, haven't ever measured it. But no plans to make it bigger, don't want the fish jumping out.
No fish harvest yet, just getting the system up and running. I just threw in some perch and bass from my pond until I could get some catfish or Tilapia. Still looking for tilapia, but did put in 100 channel cats on Tuesday. I have harvested, raddish, turnips, and peas so far. Should be harvesting some carrots, beets, watermelon, cucumbers, and bell peppers soon.
Took out about 20 perch, but we just fed them to the chickens, didn't have time to clean them. I had to leave for work right after I put the catfish in.