A small net, a small bucket and shovel, small fishing rod/reel and stuff as per Wood and ML. A worm bed for digging , rocks to throw. A small area with sand --small beach(some in pond bottom some on land). Two rules 1) have fun doing what he wants 2) when he fishes you watch (don't fish) explain what he sees while he fishes. When he gets a little bigger then you can fish with him. Start with live bait fishing -worms or cricketts. If not catching fish after a short period stop and do something else --don't wait for him to get tired and bored. A cheep pair of sun glasses so he can see into the water. I use yellow as it brightens up the under water world. Then sneak up on some BG/RES beds , or watch some minnows (and catch them with the net). Just a few thoughts.