By choice, my wild bettas are fed only live or frozen foods. I find there's absolutely no reason for me to feed dried pellets or flakes, outside of convenience. With live foods, my fish show great colouring, are almost always breeding ready, and recover from injuries with remarkable quickness. Why would I want to change a thing?
In the past, I fed my fish heavily on live blackworms. However, in recent years, they have become more of a once weekly treat than a major part of my fishes' diet. This is because I found my fish were becoming obese when fed such a rich food. Nowadays, I use them mostly as a conditioning tool, as I can't deny they do an excellent job of getting fish breeding ready.
Over the warmer months, my fish are fed almost exclusively on live mosquito larvae. These are cultured in plastic tubs down the side of my house. It is simply a matter of filling the tub with water, and waiting. A fish net is used to harvest the mosquito larvae, with the smallest larvae ideal for young fish. Unfortunately, Melbourne is cold and wet for most of the year, so I usually only get a consistent supply of larvae for three or four months. However, during this time, my fish certainly look forward to hunting down their 'wrigglers'.
I also feed grindal worms and white worms to my fish. I have read that white worms are fatty, and because of this, I only feed them in very small amounts to my fish. Both the grindal worms and white worms are gut-loaded with either grain-free dog dry food, or New Life Spectrum pellets. I'm not certain how much or if any of the nutrients from these foods are passed onto my fish, but my worm cultures are definitely thriving.
Other foods include frozen brine shrimp and frozen bloodworms. I have tried introducing frozen daphnia to my fish on several occasions, but they don't seem to find it palatable. I prefer to use the Hikari brands of frozen foods because I feel it is a safer and more quality product. Because adult brine shrimp has a lower nutritional value than freshly hatched brine shrimp, I like to feed frozen brine shrimp that has been gut-loaded with spirulina for added vitamins and nutrition.
I would like to have live daphnia form a part of my fishes' diet, particularly when mosquito larvae is scarce. Unfortunately it seems difficult to purchase even a starter culture in Australia, and so my only option has been frozen. I did manage to get my hands on a starter culture of moina, but ineptitude caused the culture to crash. The small size of the moina also meant it wasn't an ideal food for adult fish, which is what I was after.
Personally, I am not a fan of feeding meaty foods like beef heart to fish. I also do not see any need whatsoever to feed vegetable or plant matter directly to my bettas. Whatever plant or vegetable matter they consume, comes purely from gut-loaded live and frozen foods. I try to introduce as much variety into the diet of my fish as I can, and I feel this is the best way to combat potential nutrient imbalances/deficiencies.
A concept I have also embraced in recent times, is fasting. My fish don't often get fed every day. Some weeks they may go one or two days without food. I believe it's much healthier for a fish to be lean, than it is for a fish to be carrying excess weight. Fatty liver disease is a serious health problem that can face captive kept fish fed a diet rich in fat. Since I've started feeding my fish less, and fasting them more often, I have noticed a big difference in condition, when compared to my previous fish. Right now, I'm happy with how my fish look, so I'm going to continue with my current feeding practices and hopefully they will continue to thrive.
Hailing from Melbourne, Australia, I currently keep and breed a number of species from the coccina complex.