Araquanid

Araquanid boasts respectable DEF stats and an okay STA stat, making it useful for gym defense. Its max CP isn't very high, resulting in slower CP degradation and lasting longer in gyms with infrequent activity. Its resistances to common Fighting-type attackers like Machamp is appreciated, and Araquanid performs best when slotted between top rated gym defenders that are weak to Fighting like Blissey or Snorlax.

What's that? You're asking about offense? HAVE YOU SEEN ITS PATHETIC ATK STAT?!?!

Best PvE Offensive Moveset

• Bug Bite performs slightly better than Infestation for PvE offense, but the difference is not huge. 
• Bug Buzz pairs with Araquanid's Bug-type Fast Moves, and is a good move overall. 
• Despite benefiting from STAB, Bubble Beam is a poor move. And Water Pulse is even worse.
• Mirror Coat is useless. 

Best PvE Defensive Moveset

• Infestation should be chosen for defense due to it having double the base power of Bug Bite. 
• Bubble Beam lacks power but can be spammed frequently on defense. 
• Water Pulse has higher power than Bubble Beam, but comes out less frequently.
• Bug Buzz hits hard, but is easier to dodge and is more likely to be resisted by many common attackers.
• Mirror Coat doesn't provide any value unless the attackers don't like switching out common Fighting-type attackers. 

Both Bug Bite and Infestation are fairly average fast move choices, with Bug Bite being more damage-focused while Infestation is more energy-focused. Bug Bite is preferred over Infestation because Araquanid's charge moves aren't spectacular enough to make good use of Infestation's superior energy gain.

Bug Buzz is Araquanid's most devastating charge move, but it is rather costly. Bubble Beam is a low-cost shield baiting move that can greatly extend Araquanid's already impressive longevity through repeated Attack debuffs. Mirror Coat is unremarkable, but can surprise Poison-type opponents.