The short answer is you should put in exactly as much description as you personally enjoy reading. You're the one who has to be pleased with the story. Never, ever, for any reason, allow anyone else, othe rthan an editor who actually works at a magazine, tell you how much or how little description to use.
But one paragraph for a secondary character in a 5,000 word story? On a percentage basis, of course that's not too much. It may well be too little. Or just right. It depends on how well it's written, and how it brings the character and story to life.
Description is important. It's certainly possible to go overboard, but most stories suffer from the opposite. Ignore anyone who says they don't like a lot of description in stories. You aren't writing for them.
The best way to judge how much description to use in a story is to use roughly the same amount, and the same kind, or description your favorite writer or two uses. When you start writing such things as description to pleae other, or by percentage, or because somene says they don't like it, you'll almost certainly get it wrong, and have a story you don't like.