Should I fridge my P.waltl?

I have never had any problems with my spanish ribbed newt in the three years I have had it, but over the last few months it has pretty much stopped eating altogether and has rapidly been losing weight. It definitely has something to do with me moving house a few months back and moving it to a slightly smaller tank, however it isn't that small (30 liters) and has all the essentials (Filter, plants, land area etc). I first thought it could be the water quality, but that seems fine and it doesn't use the land area, it just stays in the water, relatively inactive.Thought it could also be a lack of light, so moved the tank to a brighter room, but no change. Im wondering if I should fridge the newt for a while, and see if that makes a difference? I have never had to do it before so would appreciate any advice regarding how to go about it, how long to do it for and if I should make any additional changes to the tank afterwards? Thanks

30 liters is too small. It should have at least twice that water volume. I would expect you to need greater water volume to hold a cycle with an adult P. waltl. You tested and it's OK, though? If so, it probably just doesn't have anywhere to go, and is too stressed to eat. I think fridging will make it worse, reducing appetite and metabolism. Better water quality and/or greater water volume would be my first suggestion. You can use a Rubbermaid or similar storage tub if the cost of a bigger tank is an issue. A couple floating plants are enough, you probably don't need a land area, and that'll increase your water volume. Also make sure to have hiding places so it feels secure.