I found some small animal shaped felt toys with squeakers (they are about 4" big) at a local pet store for Hot Rod when we first got him. He was 1.57 lbs when he came home. Til this day, that is favorite toy. It is a turtle with a small square on it. He loved that first one to now end, he chewed the little square off!
No matter where it is, you ask him for it, he will find it! I went and bought like 5 more so I would make sure we always had one just in case. lol. check out your local stores as they seem to have things that the bigger stores don't have. Good luck.
I also found several at Target. They have bins in their pet section. They are like 99 cents and have different types sea creatures.