I concur with duanes. In all my research, reading postings for the past 3 years by a group of experts in fish Malagascy, and having a P. polleni myself, they are used to a variety of conditions by history. When rivers on the island flood, the fish would not only get all kinds of runoff, but other streams and rivers (some brackish) would wash into the mix. They aren't so far away in generations to have adapted to prissy fish that need water a particular way, but as noted, as with any "kept" critter, extremes aren't too good. Enjoy!!