It certainly does matter.

In terms of texture and taste, white tuna may very well be indistinguishable from escolar for a lot of people. It's still much less desirable than white tuna. Japan has banned escolar in 1977, deeming it toxic.

Now we're discussing toxicity. I 100% agree that health standards need to be maintained.

Oh, yes. Yes indeed. Escolar is quite tasty - I've had it deliberately - but the gastrointestinal side effects can be very nasty. You don't want to go there when you think you're just eating tuna. This is a very underhanded substitution for a supplier or restaurant to make.

Clearly there is a difference if the other fish has negative effects.

A warm glass of milk and a warm glass of milk with ejaculate in it, can you tell the difference? Does it matter?

We were talking fish. Now you are talking about noxious adulterants to milk.

Getting an Asian-farmed tilapia instead of a US-farmed catfish would not be good.

Why is that?