Alois, I'm sorry the betta died. Sometimes we just don't know why they go. An average betta lifespan is around 2 years and they are often 7 months to a year old in the stores.
I agree with TNHawke on transporting fish in Ziploc bags in a cooler. I've done that while moving and when bringing home fish from a distant store. (30 min or more drive)




you can pick them up with your hands? i though that ruins their slim coat








