Rate the Weapon: Day Seventeen - Toxikarp, Hardmode Fishing Weapon, Terra on the Terraria Community Forum.

Fishing in hardmode corruption will get you a rotten fish with fast poison bubbles and no cost.

They are not the same weapons.One of the weapons can pierce and debuff at a lower cost than the other.

It almost feels like a pokemon trade-with-your-friend-who-has-the-other-version scenario.