James,

I am afraid I would not be able to give you a solid answer in regards to how fish are moved long distance, for that I would recommend you to ask in your local pet store for advise, after all they get their fish delivered to the store somehow (I think there are mini fish tanks for traveling available, but still you need to ask at the store).

Fish tanks are closer to my expertise. First of all, fish tanks need to be emptied, of course, and cleaned. Then, depending on a size (small ones can be packed like any fragile items using bubble wraps and carton boxes), it should be crated. Crating means building a wooden crate around each one of your fish tanks, and it takes some expertise to do it right. I would recommend you to contact several moving companies and ask if they offer this service separately.