Puffers are divided into two classes, dirty puffers and clean puffers. Valentinni's sharpnose puffers are highly poisonous to eat. Ebert, K. (2001), "The Puffers of Fresh and Brackish Water", p 19. It was a stopping place for paddle steamers and Clyde puffers. Many marine puffers have a pelagic, or open-ocean, life stage. The lifespan and breeding habits of Congo puffers are unknown. Several species of puffers inhabit the waters of the IRL. Spaceships are important because they can sometimes be modified to produce puffers. The Clyde puffers VIC 72, "Vital Spark". Puffers are named for their ability to swell by swallowing water or air when threatened. This helps figure 8 puffers to behave as they would in nature, and reduce boredom. From Rognan, they were evacuated by a large ferry and ten smaller "puffers". Figure 8 puffers grow to about long. "P. suvatti" is among the most aggressive of puffers in captivity. Such puffers are typically produced by artificial means.