That poor newt is extremely thin :S
Can i make a suggestion? would you consider acquiring other species?
Here is the thing, those newts in the shop are wild caught. They are caught in large numbers in their native homes in Asia and are imported throughout the world. This is not done carefully at all....they are exposed to high temps, they are not fed, and they are all kept together(which is a paradise for transmission of parasites and illnesses). A large number of them dies before even arriving to the pet-shops.
Those who arrive are usually ill....as is the case of the animal pictured. Their inmune system is completely shredded, and they are very prone to developing illnesses shortly after being purchased. Those illnesses are hard to treat and very often result in the death of the animal.
So you can see they are not a good choice.
However there is a large option of captive bred newts available from breeders. These are healthy, have not being taken from the wild and are a much better option for you as a buyer (and for the species, obviously).
Specially Pleurodeles waltl, and Triturus species are easily found, and are very easy and rewarding species. You can find breeders in this forum that will gladly sell you some (the UK is specially full of keen breeders).