Like Moxxi, I used Benax and he does well in this fight (H/P), so bubble open, then mudslide on CD, then tongue lash. I then had a second frog, Mud Jumper (H/B) same setup and same rotation. I had Tunder Penguin as backup, but never needed. There is some RNG for sure on this, depending on tongue lash hits per turn.
My first two pets on this strat weren't leveled. I used Benax and he solo'd the first two using 2-2-1. Then I used Tundra Penguin on Reanimated Kraken Tentacle (after I had Benax apply swarm of flies before Kraken killed him).
This team works great, done in 1 try with HB, BB ,HP. However, round 5 my first pet was swapped with Penguin (enemy "sweep" ability for highest heath pet). Continue with slippery ice, ice lance until it dies.
My scuttler was 23 AND green. SO I had to re-fight for the achievement. Tundra Penguin came in to finish up use Slippery Ice first then Ice lance to finish it out. Penguin might do well in slot 2 with the miss factor of Slipper Ice. Worked great. Thank you.
Again, breed matters, it determines which one gets swapped in when Dead Leo Sweeps. My Penguin got swapped in, and croaker didn't even see a round. After penguin died, brought back in scuttler, stampede, frost spit, finished it off.