No, cant say ive tried any of them. Ill give them a go tomorrow, id do it tonight but its kind of late lol (1:15am). He is a really nice fish and hasnt stopped moving i dont think since i got him.
Those things have a pretty strong odor to them and should entice him/her to eat. You might want to think about adding some sort of hiding place to make it a little more comfortable and less nervous. I've found XLG flower pots or PVC pipe to work well. Best of luck! I'm pretty jealous of such a nice looking cat.
There are these new oversized sinking carnivore pellets that Hikari makes called massivore delight, I feed them to the large pictus cats at work, and they love them. You can also give those a try.