Hardness is caused by compounds of calcium and magnesium, and by a variety of other metals. Water is an excellent solvent and readily dissolves minerals it comes in contact with. As water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Calcium and magnesium dissolved in water are the two most common minerals that make water "hard."
I have recently got a betta who has one curled pelvic fin that is shorter than the other. I think this is often times caused by them being kept in tiny cups and not necessarily hard water, although it can be a factor.
I like the name Chrono better than Elvis, personally. Also, he is a veiltail, as previously stated. One of the fish in my avatar is a veiltail and one is a crowntail, so you can see the difference. :)
Edit: btw, I love your username xD