Ocean kumquat

An ocean kumquat is a small, round fruit eaten in the Fire Nation. Although similar to the sea prune in flavor and consistency, ocean kumquats are much higher in protein and iron, making them ideal to be stored onboard ships for long ocean voyages.

Connections
The names of the sea prune and ocean kumquat are probably a reference to the sea cucumber, an echinodermic ocean-bottom scavenger which has been found to have medicinal properties (and is considered an aphrodisiac in the Far East due to certain aspects of its appearance). However, the sea cucumber is an animal. The prune and kumquat must be vegetable, since the vegetarian Aang is willing to try them and Sokka or Katara would surely have warned him if they were not compatible with his diet.