No, plain out, no. He is supposed to be a large, spiked, fire-breathing, TURTLE. Or more likely a tortoise, since he's not a fan of water. NOT a Kappa. It's more likely the name of Koopa came after they designed him, so the idea that the similarity between the two names doesn't work.
ok, as far as I can see, apart from Bowser breathes fire, has a spiky shell, is fat, stands on two legs and doesn't like water, I see no more differences.
Also, He is supposed to be a large, spiked, fire-breathing, KOOPA. Koopa was decided before they designed Bowser or, if not that, at the same time.
And are any of you seriously believing that they only picked koopa because it's food? The Japanese have a sense of humour you know...