I have a tiny 4 litre pond stocked with bloodworms, mosquito larvae, tiny dot shaped bugs, daphnia, cyclops copepod and 1 pond snail. May I add fairy shrimp or triops?

The fairy shrimp would probably be okay. The triops will eat anything smaller than itself (including each other). When I had them, only one made it. He ate his last buddy who was as big as him! I saw him do it. I put him in my pond where he was king for a few months. That was the first year of my pond so there were no big fish to eat him.

Triops actually eat small fish and will eat the slime of goldfish (like plecos).