First thing is I never eat anything that isnt identified on the menu then by me. If the fish type isnt listed I do not order it, there are times i will ask a waiter or waitress that I know.
There is is a fish being used by many places for fish and chips or fish sandwichs called swai, its a farm raised fish from Vietnam and I cant stand it. Its not the taste its the textures. I just cant stand it and its the cheapest crap you can buy.
Just so you know chloe just because the food you buy, vegan stuff says it doesnt have this or that in it means nothing also. That organic thing is the easiest thing to falsify. Whole foods not long ago got busted for selling organic labeled stuff that was out of season for the region and was imported and there was no way to know what pesticides or whatever they used on it.
Remember this if you dont grow or raise it yourself you have NO CLUE what you are buying. That goes for meat and vegetables and it ESPECIALLY applies to anything you buy in a restaurant.