Topo first appeared in Adventure Comics #229 (October 1956), and was created by Ramona Fradon.
The original Topo is born in or near the undersea continent of Atlantis and is a favored companion of Aquaman.
The second incarnation of Topo appears in Aquaman: Sword of Atlantis, as part of One Year Later.
This version is a humanoid octopus who aids Mera, Tempest, and Cal Durham in returning to Sub Diego.
In The New 52, Topo is reintroduced as a sea monster, resembling an octopus-crab hybrid, who Aquaman can summon and control using a special conch.