Scientist at Tufts University; my lab studies anatomical and behavioral decision-making at multiple scales of biological, artificial, and hybrid systems.
Morphological control can also use other mechanisms that are not bioelectric, so somewhere there could be organisms that don't use water all. Evolution on Earth loves bioelectric hardware because it's super convenient at enabling dynamics we recognize as problem-solving at the earliest steps. If you're going to exploit bioelectricity, I think water is important (but no doubt some future advance in materials science, gels, etc. will show a counterexample).