Gee Frenchy, here in NZ we would never admit, well not openly, that we had smuggled fish or plants, etc., in our possession.
We could expect a knock on the door any time after that from MAF.
You could then loose all your collection, even if 99% of them were legally obtained.
I heard of a guy that copped this up Coromandel way.
Lost some super-hard to get Killies too.
I tried to get them saved at the National Aquarium and/or Kelly Tarltons but to no avail.