The Fluid Pipes by default input into the tank, but you can right-click the pipe with a Standard Wrench to change it into "pull mode" if you want it to extract fluids from the tank instead. Note: a pipe in "pull mode" needs to be used with another pipe in standard (input) mode. So if you want to pump fluids from a tank to another tank, your pipe needs to be minimum 2 blocks long.
If you break a Fluid Tank, the liquid will flow out of it and will be lost (or one source block might remain). So empty your Fluid Tanks before breaking them!