Do not re-freeze fish
Fish meat are very fussy about re-freezing, it make the texture soggy and horrible to eat. The reason is that the water content in the cells got frozen and at negative degree Celsius, the water expanded and causing the cell wall to break. Once thawed, the water flow out of the ruptured cell, and repeated refreezing allow the water to be frozen and expand again, and these induces further damage to the cells, and hence the texture of the meat turn soggy. Hence, best to eat fish fresh without freezing if you can, and if unavoidable, do it only once.