The Pumpkin Octopus is colored mainly pink, fading to a darker pink towards its head. Most of its head, however, is covered with a pumpkin. This is bright orange, with a stem and two leaves at its top fading from dark green to a sickly yellow green, and a hole carved in it to show the Pumpkin Octopus's face. This hole is designed like the mouth of a Jack-o-lantern, with two smaller eyeholes above it.
To obtain this fish, you must play in the Halloween Tank, either with a Season Pass Ticket or by playing when the Halloween Event rolls around. You have to own the Hungry Coffin structure and have 5 Seahorses in your Halloween Tank for it to unlock. Once unlocked, it costs an amount of Vitality that rises each time you create a fish (like the normal gameplay).