I'm relatively new to livebearers but not new to aquariums at all. I've kept high tech planted tanks, Discus, and Reef Tanks, but ironically I've only ever had a couple of livebearers in the past. I've never really had much interest in them until recently when I started to pay close attention to Livebearers Unlimited in TFH. I've often perused this column, and if something caught my interest I'd read it, however recently I've started to take more of an interest in it and read it regularly every month. I have 4 years of back issues to read through but I am really interested in the possibility of doing livebearers in my new 125gal Natural Planted Tank. My pH is 6.4 (out of the tap) and my KH and GH are both ~1 degree.
Now to my big question. Is it just a myth that livebearers like hard water or is it fact? If so, is my water too soft to have anything survive?
Many of the livebearers common in the hobby do like their water quite hard.The reason they are common in the hobby is because few people have the ultrasoft water that you are working with.
Livebearers appear in almost any environment on earth, even in the oceans, so the right livebearers probably exist for water exactly like yours. Unfortunately, many of us here arrived at livebearer keeping partly by having that hard, high pH water. You could make suitable water for typical livebearers by using calcium carbonate in one of its many forms in the flow path of your filter. A nice average kind of livebearer water for many of the fish we tend to keep would be between 7.2 and 8 on the pH scale with a GH and a KH both over 5 and for some fish over 10.