Are you poking around in your Necturus enclosure a lot and moving things about? Your mudpuppy probably just needs some time to acclimate to his surroundings without the constant stress of a huge primate messing with his stuff and flipping over his hides or what not.
Don't worry so much or you are going to burn out and your mudpuppy is going to be very stressed.
Also, could you please limit the threads on your mudpuppy? I know you are happy with him and really curious, but this could have easily been posted under the old topic. If you keep everything together it is easier for people to help you and it makes it easier for people to find the topics they want or need.