The Infinite Hatchling has to die on Turn 3; if not just give up.
Yula has to be dropped to 117 health, so save Life Exchange if Snozz only hits her one time and Breath instead.
It really really helps if you can get a critical hit.
I didn't succeed before all these things happened. Perservere!
This is IMO the hardest fight for the Family Fighter and I purposefully left this fight for last. Once I finally succeeded, I decided to share the Strat I used to win. Warning: There is heavy RNG BUT it neither involved 3 weeks of farming Celestial Tournament for Yula nor needed a rare/specific breed of Twilight Clutch Sister (which I was waiting over 2 week for on the AH).
1st Pet: Nether Faerie Dragon: x/2/1 I highly recommend (H/P) breed with 1465 health because:
A) The large health pool will allow NFD to survive 3 attacks from Snozz, reducing RNG
B) A wild Nether Faerie Dragon's most common breed to catch is (H/P)
Possible substitute for NFD: Yu'la or Sprite Darter Hatchling. But honestly, why are you here looking at this strat if you have Yu'la?
DISCLAIMERS: 1) This is a HEAVY RNG fight requiring AT LEAST 1 of 3 possible critical strikes. 2) 2nd pet (Dark Whelpling) must have more health than the 3rd pet (Azure Whelpling). 3) I didn't test it myself nor would I ever do this fight again but... A friend informed me the Albino Chimaerling as the 2nd pet and Emmigosa as the 3rd pet is not a viable combination. 4) Call Darkness is vital to this strat. It's "buff" will reduce accuracy of all pets by 10%. If this causes one of your attack to miss then restart the battle. 5) IMPORTANT bring bandages and have patience. Unless you're really unlucky, this shouldn't take more than 25 tries.
Now on to the Strat:
Round 1: NFD is forced out to Dark Whelpling (or 2nd pet). Round 2: Swap Dark Whelpling back to NFD Round 3: Life Exchange. It's uncommon with (H/P) breed but if NFD dies BEFORE life exchange; restart the fight. Round 4: NFD is forced out to the Dark Whelpling (2nd pet). Round 5: Call Darkness (Hope for a critical -- it's rare but if you don't get one don't worry, just continue. You'll have two more chances to get a critical). (Additionally If you miss any of the next 4 attacks as a result of Call Darkness' 10% reduced accuracy then restart the battle). Round 6: Tail Sweep Round 7: Dark Whelpling (or 2nd Pet) is forced out to Azure Whelpling (or 3rd pet). Round 8: Claw (Hope for a critical). Round 9: Surge of Power (Hope for a critical). If Azure Whelpling is hit more than 5 times by Snozz's flank prior to casting Surge of Power then Azure Whelpling will die and you must restart the battle.
GG! If you made it this far, you've won. And if you saved this for your last pet battle for the family fighter achievement, then you can hearth from this frustrating hellhole and never look back.
Please comment if it worked for you! Or comment if you see room for improvement!
37 times using this strat with the breeds suggested and no luck. Tried the original strat 25 times and no luck. One of the most rng fights I have ever encountered and the last I need to the meta pet battle achv in Argus. Not sure what to do at this point, very frustrated.
Swapped Yu'la out for the higher HP Sprite Darter Hatchling (1, 2, X). Since Breath wasn't OP against Critters, Slicing Wind is actually stronger because it can hit up to 3 times. During the Breath, LE, Breath phase, just option in Slicing Wind and you'll guarantee that Surge of Power will destroy Snozz like it should.
took a few tries but since these were the only dragons i had from the suggested ones, i had to make do.
some quick notes, infinite hatchling HAS to die on his turn (75%). and Slicing wind has to hit at least 5/6 times (under 50%) or this fails. i got a bit unlucky with rng, but it will defo take a few attempts. but it DOES work.