Night crawlers and red wiggler worms are safe and nutritious, I just wouldn't catch them as they could have parasites and potentially have toxins given the environment. I get my worms from Uncle Jim's Worm Farm: https://unclejimswormfarm.com/ They have great quality control and healthy worms. They are easy to keep and breed, as well so you don't have to buy them very often. The red wigglers are smaller than the night crawlers and also reproduce much faster.