Terraria (Wiki): Purple Clubberfish

The Purple Clubberfish is a melee weapon that pierces enemies.

The Purple Clubberfish is one of the most powerful weapons in the early stages of the game. It's a rare fish that can actually be used as a weapon.

When normally used, the Purple Clubberfish will not emit light, and attacks do not go through walls. It has the second slowest use time making it less effective against fast-moving enemies unless the player times the attack correctly. A Purple Clubberfish cannot autoswing. Its attack reaches five tiles in radius. At an optimal distance, the Purple Clubberfish can pierce two enemies. However, multiple bodies will be damaged should they all line up for the player.

Combat-wise, the Purple Clubberfish has the strongest knockback, making it effective against waves of enemies. The Rockfish outperforms the Purple Clubberfish, which deals the same amount of damage, attacks more quickly, and functions as a Hammer (3DS). All Flask items will imbue their unique effects since the Purple Clubberfish is a melee weapon.

The Purple Clubberfish is best modified with Legendary for overall stats improvement.