I guess GameFreak is a fan of "Finding Nemo"
Anyways, Golisopod isn't the only "Magikarp" we got in gen 7. Wishiwashi also fits into this party, and while it looks good on paper with 140 stats in offenses and similar in defense in its Schooling form, Wishiwashi unfortunately lacks speed and has a meager offensive movepool to be a proper powerhouse, and 45 HP hampers its ability to take hits as a tank or a wall. Not to mention it becomes next to useless if its health drop to 25% or less. Much as I would like to love this legion fish, I just can't get past its issues despite its cool gimmick. Sometimes a school is only worth the sum of its parts in this particular circumstance.
Discount Jaws
Item: Life Orb
Nature: Quiet (+Sp. Att. -Speed)
EV's: HP: 252 Att: 4 Sp. Att: 252
Moves:
Hydro Pump
Ice Beam
Earthquake
Endevour
Set Details:
A mixed tank that tries to play into all of Wishiwashi's strengths. Hydro Pump is the most powerful STAB, Ice Beam handles Grass types and Dragon types, Earthquake is for Electric types and has good general coverage, and Endevour is just assurance that Wishiwashi won't be completely useless set-up bait once below a quarter health. Life Orb boosts all damage, EV's are pumped into HP for bulk and Sp. Att. for damage.
My Name is Legion
Item: Leftovers
Nature: Bold (+Def. -Att.)
EV's: HP: 252 Def: 156 Sp. Def: 100
Moves:
Scald
Toxic
Rest
Sleep Talk/Aqua Ring
Set Details:
A bulky set that relies focus on whittling down the opposition while maintaining your own health. Scald is the gold-standard for bulky Water types that does decent damage and has a 30% chance of burn, which is welcome to scorch off the opposition's health while halving their physical attack making you all the harder to KO. Toxic is a defensive mandatory to help Wishiwashi outlast in long skirmishes. Rest is the only form of recovery sadly, so Sleep Talk should be considered to compensate for the two turn cooldown, but you can consider using Aqua Ring instead just to give you an added source of recovery.
Gotta feel sorry for all the Wishiwashi, but at least they get to hang out with best girl: