Ok, so I came home today to see my Sunburst Platy staying still and sinking until something comes to eat it, then it swims away. But the weird part is, her lips are still open but they look somewhat crusty. Picture her lips being fried open. Thats all I could really say. All other fish are fine except for her. she had babies about a week ago if it matters. Please any medicines or what it is would be great, thanks!