I am a college student flying home for the summer and I want to take my fish (a beautiful blue betta named Horatio) with me... any recommendations for going about this?

I called the airlines and the only thing they suggested was that I either put him in a container with less than 3oz of water or get a doctor's not stating that my fish is necessary for my mental stability while on the flight in which case I would have no restrictions...

I've looked up information online about this question and have found that numerous people have had no trouble flying with fish... but I'm curious how to go about this with the 3-1-1 rule with TSA. My betta can simply not fit in 3oz of water for very long.