Thunder Fang is a Normal-type move, while Tyranitar is a Rock/Dark-type. Pokémon can only learn moves of their own types or those that are specifically listed in their movepool.
Here's why Tyranitar can't learn Thunder Fang:
* Type incompatibility: Thunder Fang is a Normal-type move. Tyranitar's primary typing is Rock/Dark, and it has no Normal-type movepool access.
* No Movepool: Thunder Fang is not listed in Tyranitar's movepool in any generation of Pokémon games.
Even with the use of TMs, TRs, or breeding, Tyranitar cannot learn Thunder Fang. It is important to note that the movepool for each Pokémon may vary between different generations of the games.