The other day i bought a dalmatian lyretail molly for my nephew. He as a 10 gallon tank that currently has 1 leopard guppy and another molly of some kind. His water parameters were fine, can't remember what they were exactly but they were perfect. The new molly seemed fine at first but the next day it was just laying on the bottom of the tank. After I saw that, I moved it to a 5 gallon container with a filter, heater, and air stone. I added some aquarium salt to the container thinking it might just be over stressed. It will come up for food and swim around sometimes but mostly stays on the bottom of the tank. It looks fine except it keeps its dorsal fin down. I was just hoping someone here could give me an idea of what to do. Thanks in advance.