This article was originally published here.

Your choice of keepnet should be based on its shape, length and buoyancy. 
1. Shape

Round : takes up little surface space so less chance of snagging on the sides.

Square : remains more stable in the current or on dykes (when used in canals or rivers).
2. Length

Choose the length of the keepnet (1.2 m to 4 m) based on the hight of the bank. A 2.5 m long keepnet allows you to deal with most situations.
3. Buoyancy

Floating keepnets are ideal for fishing from a boat or Float-tube as well as for speed and "roaming" fishing. They allow you to keep your catch close to hand as it drifts behind your boat.