Riverfruit was a fruit native to the planet Alzarius in E-Space. Riverfruit resembled an Earth watermelon. It appeared to be part of the staple diet of the Alzarians, who apparently farmed it as a crop. The exterior of the riverfruit was dark green, whilst its interior was typically dark yellow.
The Alzarians considered riverfruit theft a relatively serious offence. The Outlers led by Varsh stole a number of the fruit from a pile near a river. Adric, in a bid to prove his worth, also attempted to steal some but was spotted and dropped them in his haste to escape.