It wasn't exactly related to the hobby, but I was a zookeeper for five years, and took care of a 10,000 gallon tank (freshwater though). We had a stingray touch tank once (didn't work out well at all, mangement had thier heads up thier butts and wouldn't listen to those of us with actual salt water experience)
I have also worked in several LFS in the past.
Right now me and my husband have a side business of building custom aquarium stands, we also set up tanks for people and I hope to have some maintenance contracts soon. I don't expect to make a ton of money, just get out of the house a bit doing what I love, supporting my hobby.