I would suggest that if you are serious about creating a quarantine facility you should get the standard and also apply for a building consent from your Local Authority for the purpose of: "the importation, quarantine and breeding of fish," and get the written consent of the Regional Council for the discharge of effluent to the ground. Then construct a building that meets the requirements of Maf (that shed will not)
Any building that is less than 10sqm and one story high does not require a building consent if it is at least the same distance from the boundary as it is high (the one in the picture is not) unless it is for certain purposes like what you propose. (a garden shed doesn't, a quarantine facility does).
In summary: You will need to comply with the Requirements of Maf (NZS 154.02.06), your Local Authority (Building Act and RMA), your Regional Authority(RMA) and you will need to be listed in the gazette.
Most of the above will require site visits for which you will be billed.
You may need an application under RMA (which could involve a hearing at your expense) at either or both the Local or Regional Council.
Good Luck. If you succeed I could be in the market.