sick fish

[platybreeder26]

My guppies are sick. They are at the surface and some of them are pale, all of them are bloated, cant tell if the females are heavily pregnant or bloated, and one of them has black poop. What is this, and what can I do to help? I currently am doing frequent small partial water changes, dosing with melafix and feeding peas. One of them is hiding behind the heater.

 

[coralbandit]

Do they show signs of Pine coning?( scales sticking out/dropsy).
If so then the issue is bacterial and mela fix will do nothing IMO.
Since the fish look stressed do you have a test kit to provide parameters?
If not how about tank size ,how long set up ,who is in it and water change schedule(how much how often?).