In an attempt to escape from the attackers who had destroyed their spaceship, Leo Fitz got recruited on Viro's ship, which transported several breeding tanks of Xandarian Snails. Fitz's work on the spaceship increased the fertility of the snails. Although he initially posed as a Sivian with the help of an Iriscope, Fitz's human nature was revealed to the rest of the crew when he expressed disgust towards the animals.
The snails transported on the ship eventually perished when Fitz tricked Viro into opening the wrong airlock in the spacecraft. Fitz remained unaffected by this loss since he had little taste for the creatures.
In an alternate timeline, during the dinner of Kasius and his guests in his suits in the Lighthouse, Gaius Ponarian offered the diners Xandarian Snails as a goodwill gesture for Kasius, who made it possible for them to see the Quake, the Destroyer of Worlds. When Ponarian witnessed that Leo Fitz was not eating the snails, the latter claimed that he found moist creatures distasteful.
According to Enoch, Xandarian Snails are made fertile by efficient carbon dioxide scrubbers.