I've been using distilled for all my arachnids for years without problems. The "essential mineral" argument isn't good - not many essential minerals in rainwater or most surface waters. The major criticism I've heard against distilled water comes from people who work with water chemistry, but the hypothetical "true" distilled water they are concerned with doesn't last long as such when it's splashed or sprayed into a cage or water dish.How is distilled water not good for live animals? It is the water we are told to use for all the living animals at the lab I work in, both invertebrates and vertebrates.