n 1968, when I was a junior in college, we went on a school trip and stopped in London at the silver vaults, where I suppose I was taken for a ride, as I was 19 years old and American. Nonetheless, I still have this fish set and it’s very pretty, but there are no marks on it at all. Can anyone please help me know something about it? It’s probably not silver, so what would it be? They are contained in this nice but unmarked box and I think there probably was a service for twelve, as there are six more little slots. Thank you so very much.I really appreciate your help.
Fish knives were a Victorian invention, and became all the rage - no well-appointed home could be without a set. They were designed to deal with boney fish, which people had always just pulled apart with two forks. But the forks remained the best method, so the fish knives were never used, and survived in their millions. One of the appraisers on Antiques Roadshow said that they always saw fish knives - lots and lots of fish knives. 
Certainly not sterling, and given the complete lack of markings, probably not even silver plate. Most likely an alloy of base metals, like nickel, copper, and zinc, which is easy to work, and very resistant to corrosion. Identification is virtually impossible.
Even as a complete set, you’d probably have trouble selling them on eBay at any price, but as an incomplete set…
On the bright side, this set certainly brought joy - to the heart of the dealer who flogged them to you. I’m sure he was positively giddy for the rest of the day. 
I spotted a complete set - six knives and six forks - of almost identical design, and in the same type of box, that sold on eBay for $30. But those were, in fact, clearly marked EPNS, so they were silver plate. You get the picture.
Well, I have to say your reply certainly made me laugh! How nice to know that I brought joy to the heart of the dealer Who assured me they were silver and Victorian.Well okay, they’re Victorian. I thank you so much for getting back to me and so very quickly.It was very interesting to read and while i’m not delighted to know Of their lack of monetary pvalue, I am happy to have expanded my knowledge base! Thanks again. Sincerely, JRC
I suspect that every collector has a few things like this kicking around - youthful mistakes, or even not-so-youthful mistakes. I’ve heard some Antiques Roadshow appraisers admit that they’ve been taken in by totally bogus, made-in-China-last-year fakes, sometimes very recently.
The dealer might have mumbled something about “nickel silver,” which would have been honest. But nickel silver doesn’t contain any actual silver. Easy to be taken in by that!