Is it good for battles?

[Excalibur0126]

Here's a few movesets from Smogon. They're for Little Cup, but I'm sure you can somehow make it work with some edits and such.

Corphish is a great wallbreaker and late-game cleaner thanks to Adaptability, a great ability that boosts the power of Corphish's STAB moves by 50%. Backing up this ability, Corphish has great STAB moves in Crabhammer and priority Aqua Jet. Corphish also has access to Knock Off, a great move for a wallbreaker. Although Corphish has access to two boosting moves in Swords Dance and Dragon Dance, it faces competition as a setup sweeper from Scrafty, Talonflame, Carracosta, and Omastar. Corphish's flaws lie in its only decent physical bulk, fairly mediocre special bulk, and sub-par speed, albeit it's still fast enough to outspeed most walls. Lastly, Corphish struggles against prominent threats such as Chimecho, Whimsicott, and Toxicroak.

Wallbreaker
Corphish @ Eviolite
Ability: Adaptability
EVs: 196 Atk / 76 Def / 236 Spe
Adamant Nature
- Crabhammer
- Knock Off
- Aqua Jet
- Swords Dance

This set is fairly straightforward to use. Removing Eviolite is really helpful for Corphish and its partners; hit opposing switch-ins with Knock Off, use Swords Dance if a boost is needed, and then attack with Crabhammer or Aqua Jet afterwards, or just switch out if they threaten Corphish. Try to keep Corphish alive against stall and bulky teams, as Corphish is great at weakening walls and bulkier Pokemon.

Dragon Dance
Corphish @ Eviolite / Life Orb
Ability: Adaptability
EVs: 196 Atk / 76 Def / 236 Spe
Jolly / Adament Nature
- Dragon Dance
- Crabhammer
- Knock Off
- Aqua Jet

It is usually best to have Corphish set up late in the match, after its checks, which include Amoonguss, Toxicroak, Chimecho, Magnezone, and Whismicott, have been heavily weakened or removed. Despite this, Corphish possesses a great deal of utility with Knock Off and strong priority, which can be useful throughout the match. Corphish can support its own sweep by removing its checks' items with Knock Off earlier on in the match.

Choice Band
Corphish @ Choice Band
Ability: Adaptability
EVs: 196 Atk / 76 Def / 236 Spe
Adamant Nature
- Aqua Jet
- Crabhammer
- Knock Off
- Switcheroo

Early- to mid-game, Corphish should be using Crabhammer and Knock Off to weaken switch-ins. Aqua Jet is used for revenge killing and cleaning late-game. If Corphish finds itself on the field against a faster Pokemon, it is, in most cases, best to switch out given its frailty. Slow Volt Switch and U-turn teammates are therefore very important for that reason. Switcheroo is best used on a predicted switch-in mid-game if it's unlikely for Corphish to clean with Aqua Jet later.