AquariArt, earthworms have always been suggested for predatory fish and yes, they are indeed very high in proteins which is why they are unsuitable for purely vegetarians. As far as cleaning them before feeding to the fish, use damp tissue papers so they will excrete the soil in their body thus they become 'clean' for food consumption. I'm not surprised earthworms are eaten by some people around the globe.
This is the problem with bloodworms. While bettas are certainly carnivorous, a high protein intake can be very dangerous. As I mentioned before, proteins are not easily digested and could easily accummulate inside the internal organs thus resulting in digestive problems.
The only reason most people insist on soaking the pellets is that pellets tend to increase in size when soaked in water and if the fish eats them rather quickly, the fish is bound to 'inflate' thus suffering from digestive problems. Like most of us have said before, feed sparingly. Many people unfortunately are quick on the uptake to feed the fish thus the fish looks severely bloated after several minutes. Same thing can be said with flakes.
