Ok, 2 questions.....

1. How do I achieve a true black without giving it such a horrible taste? I tried a couple weeks ago, and after using half the jar of paste I just use the dark grey color I had. I even tried adding it to chocolate icing so that I started with darker icing. Do they make a no taste black?

2. Is there any way to get silver? I'm doing a fish.

I mean it depends on what medium you are using. Marzipan takes color brilliantly. So it doesn't take as much to get you there.

You can get a pearly-fied fishy look with dusts. There are silver dusts.
Some are stronger/deeper than others. I think the stronger ones are called silver highlight or something and maybe a little less edible than it's non-toxic friend nu silver luster dust. But you can mix them with a liquid high in alcohol content like lemon extract or vodka or something and actually paint it on.

You can make black paint with alcohol & black color too. Airbrushing black might not get you a real true dark black but you can paint with it.

And there's black edible ink markers too. If you just need dabs.

I can't answer your silver question, but for black I always use Duncan Hines Dark Chocolate Fudge frosting.

For silver or gray I mix one part Wilton Black with one part Wilton Blue.