Fujiya carries many brands, and many of them are unseasoned. I am tempted to think that companies like nutrafin get their nori from the same makers that produce the 'human grade' stuff...

ive seen lfs feed lettuce and spinach even though they know it's much better to stick to nori. they do it because nori isn't nearly as cheap as a head of veg.

lettuce
 

That happend 10 years ago.All the fish only took 1 or 2 bites before they acted really weird I thought I would lose them all/it was close.Just think we eat that stuff.

unseasoned nori
 

SuprStore oriental isle next to the pet food, two kinds to choose from.