[Balimon]

Epic mage pet is excellent for raiding for a couple reasons. A max level water pet will parse higher, but often you only get to summon it once, and it probably won't be max level. The epic being the same level every time is a huge advantage because on average it will do more than a water pet simply because of RNG.

Secondly you can use the epic pet mana free, because it's already summoned on a charged orb. This lets you have the mana you'd use to summon on a one off fight, let's say a random dragon in NToV where you can use pets, like Lady M if you've cleared enough of the trash. In that situation you're getting a guaranteed amount of DPS from the pet, and it doesn't cost you 400, leaving you enough to drop two more rods for the clerics.

There's a reason mages stop using focused water pets after getting the epic, and while pet use in raiding is certainly debatable, they are still used plenty enough that the epic mage is getting more DPS over time than they would with water. There's nothing worse then summoning the lowest level pet on a fight where it matters, and is resummoning during combat really worth it?