I wouldn't worry about 12 gram weight loss or a 3 month feeding strike. If it was faster loss then worry. I had a male last year go 10 months. He lost 60 grams the entire time ( and gained it all back in 2 weeks). Like Deb said put him in a smaller tub. And be patient. He will feed again when he is ready. Can't stress enough tho. Be patient with him. They can be very stubborn