Betta splendens, the common aquarium betta, is a largely carnivorous fish that is a poor hunter and feeds mainly on things like mosquito larvae. They will appreciate any live or frozen food that is small enough for them to eat easily. Crickets are likely too big although I am sure they would try to eat them. The Betta splendens is one of the most colorful fish that you could get for your peaceful community tank. Although they have a reputation for being aggressive, I find that they only show aggression with others of their own species. With other fish, they are more likely to become victims in most cases. I have two nice large veiltail male bettas. One is in a 120 gallon community tank with mainly larger fish while the other is in my 45 gallon endler breeding colony, doing his best to help me with the population explosion, and enjoying good easting in the bargain. Unfortunately, a mature breeding endler colony produces more fry than he can handle. I find a betta as easy to care for as a guppy. Just run the water at least 75F and they will thrive for you. They can be expected to start building bubble nests if you keep them at 80F.