Universally the fish symbol has been found to represent fertility, success, good luck, harmony and emotions. The fish has evolved through millions of years and also represents the power of change , transformation and growth.

If you want to combine the fish and skeleton into one earring (like the picture where the fish is red and the skeleton is white), I recommend printing the 6mm height model. 

Otherwise just print the 1.2mm height, this is solid and fits the hook of the earring nicely.