About 5 inches long, tan brown with white-rimmed black spots at regular intervals along its length. Slender and eel-like. Not especially slimy. Tapered, pointy face/mouth.
Found under a rock in the intertidal zone in a sea loch on the northwest coast of Scotland.
Looks like it.
And urgh. I did my icthyology class project on gunnels way back in the day. Disastrous failure.
I’ve hated the cute little bastards ever since ;).
It’s a baby Nessie!!!
If that’s anything like Hawaiian butterfish it is quite nearly the most delicious food known to mankind. Unfortunately also partially undigestible. And while it won’t make you sick, exactly, there are oils which will, er, leak out of their own accord. . .
I don’t think it is even distantly related.
I know, but not all fish are eels, even some that looks like eels - the purpose of writing the title that way was actually intended to try to forestall terminology nitpicks. 
That looks spot on, thanks.