How can you get Facebook credits in happy aquarium on Facebook?

There are a few different ways ...

1.) You can do various surveys or sign-ups for credits. An ex. would be to sign up for a 90 trial for another website, or answer 1,000 personal questions for data/ geographics.

2.) Use your credit card. You can simply click on "buy credits" and they will give you amounts for purchase.

3.) You can use a Gaming card. I don't know to much about this one but ...its an option.