Use egg crate zip ties and a large rubber band for the trap door. Make a box with the eggcrate and leave 1 side like a door. If what u are trying to catch can slip thru the holes then take a lufa(shower sponge ball thing) cut the center string and its a giant net rap the net around the cube and ur set
i have one you can borrow. unfortunately im in east islip long island. if you want to travel for it lmk. it is all acrylic and it was large enough to catch my 8" pink tail trigger. my email is [email protected].