There is no 'fly pattern registry' nor are there any fly police who will confiscate your vise if you try to tie some protected pattern. You could try to patent your fly pattern but it would be a difficult thing to patent a fly pattern and make money off that for the following reasions:

1) Patents are expensive, try 10-15 thousand dollars. It would have to be a pretty earthshaking new pattern to warrant that expense.

2) It is really tough to invent a totally new fly that is unlike anything that has been published before. The first publication that described fly tying and fly patterns was published BEFORE COLUMBUS DISCOVERED AMERICA so there are 500+ years of prior art on fly patterns, all of which could invalidate a potential fly patent.

3) Again, there are no fly pattern police so it is up to you to hunt down any party that copies your patented pattern and haul them into court to enforce your patent at your expense.

That said, there are two recent fly patents that I know about: Jim Teeny patented the Teeny nymph but I think that patent has expired (you should check for yourself before you tie any Teeny nymphs), Waterwisp has patented some of the hook modifications that allow them to produce thier style of (upside down) fly. You can buy their special hooks from them on their web site.

You might have better luck with tradmark and/or copyright. I know that a copyright only costs about $50 and you can copyright written word, art, photographs and even computer code. You will have to dig around in copyright law wrt fly patterns yourself as I am a patent guy (I have 7 but none on fly patterns) and don't know alot about trademark and copyright. I do know that Orvis recently had a deal where you could send them a fly pattern and if they liked it and wanted to offer it in their catalog, you would get a royalty. You might want to pursue that.