How bout Gar? Think hey have strong enough armor to withstand attempted gashings?
Could work. My Cuban has taken fair bit of beatings thru the years. I can see scratches across its body but never ever seen any missing scales - it is that tough.
The tail and eyes might be vulnerable though - as ATFs are known to take out eye balls.
Another risk is whether the gars will retaliate or not. They can give as well as receive. LOL!
It might take some effort but you can try to get some docile gars from trusted hobbyists who comm and know their behavior.