My gerbil fell ill 10 days ago, he was cold and inactive, but later eating. We moved them next to a radiator, he continued to improve, but a few days ago we noticed that he had lost a lot of weight, he has always been skinny, but his spine was very pronounced, and he would not eat. His eyes were half closed. The next day he ate 4 mealworms, some bread and some strawberry, but would not drink. Today he ate some bread, strawberry and a Mealworm. He didn't take anything dry like seeds. Seems to have more energy, he drank. Eyes are still dull and half closed. Any ideas of what is wrong with him.
Sorry to hear he isn't feeling well. It sounds like he needs to see the veterinarian. When a gerbil is losing weight, one thing to check is his teeth. If his bottom teeth are overgrown, your vet can trim them back. If this is his problem, he will need them trimmed once a month or so. He may also need easier-to-eat food. Best wishes with his care.