I haven't heard of fish choking. Some of the photos I've seen of fishes eating "prey" the same size as themselves seems to indicate that they do not, but I have seen and read about "FSDS" (Fishes' Sudden Death Syndrome.") It is quite common in fish in the genus _Corydoras_, where the fish swims quickly to the top, sucks up a gillfull of air, and immediately dies. It looks for all the world like the fish had a heart attack. Bettas do not seem to have a predeliction for this, but never say never, especially when dealing with fish. Then again, maybe it was just her time. BTW, that white betta in JMS' post is gorgeous. There aren't many pure white fish, are there? That one is just lovely.
Best fishes,
Mary Ellen Sweeney