Mine is a round design, 4'deep (below waterline) x 4'diameter. It's 1/2" mesh, with 3 circles of 3/4" black plastic pipe as the framework. I haven't found the need for a lid, or any shade as of yet.
The white plastic pipe is the attachment arm, it hinges at both ends to allow the cage to rise with the water level, but not drift side to side. I attach it to the concrete deck, where the water level is 6'
The mesh is common hardware store stuff, overlapped in the middle to create the depth I needed. I started off using zip ties to secure the mesh to the pipe, then discovered that weedeater line could be used to "sew" the mesh to the frame...works great. I use pool noodles, or pipe insulation to float it. I replace the floats every year, and have had zero problems with the foam deteriorating, or with the fish pecking on it.
I let it overwinter empty in the pond the first year, when I removed it in the spring to clean off the algae buildup, I was amazed to find a half dozen LMB in it. They were between 3-3.5" long, too big to escape through the mesh. I can only assume they entered when they were smaller and became trapped.
"Forget pounds and ounces, I'm figuring displacement!"
If we accept that: MBG(+)FGSF(=)HBG(F1) And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1) Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT? PB answer: It depends.
