He doesn't look skinny to me, just empty. My normal guy has probably lost 100g too, he was around 1050g and now he's around 950g, but I honestly think most of the weight loss was just the clearing out of the digestive tract. He has been off food since early February and hasn't really been pooping at all in the last month and his weight has remained stable since then. I'm not worried, I'm just offering weekly and hoping his appetite returns soon.

Something is odd with your guy's tail though.