octopus
鱆 centers on the octopus, a sea creature with eight arms. The meaning is specific to this animal.
鱆 combines 魚 (fish) with 章, which likely provides the sound ショウ. The character was created to represent the octopus, a sea creature associated with fish.
The left side 魚 means fish, and the right side 章 looks like a pattern or badge. Imagine an octopus wearing a patterned badge as it swims among the fish.
For ショウ, picture an octopus putting on a show for the fish: show -> ショウ, and the octopus is the star of the sea.