Eh, maybe, but unlikely if you ask me. They had to reach a temperature above the freezing point of water to melt, right? Ammonia boils around 28 below zero Fahrenheit, so the Venber would probably have to exist in temperatures well below that. Getting that kind of temperature consistently is a stretch, even in the arctic, and if it was that cold, the Animorphs wouldn't have been anywhere near as well off in their morphing outfits, even for the short periods of time that they were in them. That, alone, leads me to believe that any liquid on which their form is based would probably have to have a boiling point over the melting point of water. It sounds as though at least part of their structure would have to be based on water ice, though.
