First frog tank ever. Probably need help

[Colorblizzle]

Just looked at the description on the site I bought it, it doesn't mention anything about a minimum depth. I know it sucks water from the bottom

http://www.drsfostersmith.com/produc...p;pcatid=23458

[Mentat]

That filter is designed for aquariums and might require to be submerged. Did you tried the test described in my previous post? If it does not work with 3 in.; then add more water to container until filter is covered and see if it starts working. If it does, then that model filter won't work for your tank's 3 in. water depth. If it doesn't start; then filter might be broken.