Any new animal needs to adjust to being in a new place. Ball pythons take a week or two to adjust to their environments to become comfortable.

If your snake doesn't feel safe in its new environment then it can become stressed which can lead to food refusal or health issues.

Sounds like your snake is just cruising around and just slithered through the water and around the cage. For the first week or so, he might cruise a lot looking for a way out of the tank. Its normal. Once he starts spending his days (and most nights) in his hides, then you know he is settled in and feels safe.