Shell Game - S2-E9
Revealing mistake: While Maureen and John are piloting their two maintenance pods, in the closeups which face each of them head-on, note the walls behind them have numerous identical smudges in their individual pods, which is especially noticeable in consecutive closeups.
Answer: It's unknown how the eels got into all the fuel tanks. Once they were discovered, the colonists could flush them out of the tanks and keep them out before adding the fuel from the Jupiter that crashed in the desert.
raywest ★