KlondikeGeoff they do have other flavors if your three-legged hopper detests the tuna flavor. I know Laxatone brand has an “original” flavor that some cats like. It’s red, as opposed to the blue packaging on the tuna flavor. I have no idea what it’s supposed to be flavored, most likely a generic “meat.”
My cats go crazy for tuna laxatone, so I haven’t tried the other flavors. You could try smearing it on their noses, as they hate stuff on their noses too.
Want to swap a couple of cats? 
Heh, I’ll try the nose bit tomorrow.
They also make hairball treats with yummy petroleum jelly centers in a crunchy shell. My feline bottomless pit will scarf as many as he can scam off me and take away from my Picky Eater. My Picky Eater will grudgingly eat one.
Petromalt tastes like Malt and many cats like it. Some will lick it off my fingers greddily, other require the first couple of doses be rubbed into their mouth. Get them to open their mouth a tad, then wipe your finger in- some will go inside the rest around the mouth, but they’ll lick that off.
Nutrimalt - according to every cat I know- just plain tastes a lot better, and I will sometime cover Petromalt with a thin layer of Nutrimalt- they’ll start licking the Nutri and then finish the Preto as they have a similar flavor.