There is a chemical that is supposed to contain some form of oxygen that comes in this liquid. A lot of breeders ship the Bettas they mail in this fluid. It is supposed to keep them alive with no care for a few days. It is probably better than the standard dirty water you see many little guys in but only if it is kept clean. It is what they use to take the place of filtration supposedly. I think it works for shipment but not for full time immersion in petstores.
the blue water is usally a tablet that is droped into the water and it supersaturates the water with O2 allowing the betta to live longer tho he might be hungarier when u get him....that is all it does. the down fall to it is that when the Betta starts using the bathroom, the ammonia will build up and push the oxygen out too so i would think that this method is only used for transportation.
if u look at petco u have the vibrant ones for like 7 usd ea and then u have the ones that look like they will be dead in a day or so for like 3.50 usd that is the discount shelf and the petco by me only sells crowntails tho there are some beautiful ones..