OK then. (Oops... too slow! Zags beat me to the post!)
1- don't change your filter media... your tank is almost certainly still cycling and the filter pads hold all of the beneficial bacteria that keeps your tank healthy. (more on this in a moment.)
2- do PWCs-- for a healthy tank, a weekly PWC of ~20% is warranted... I would do a 50% change immediately, as your fish seem to be showing signs of poisoning. When you add water back in, first treat it with dechlorinator. The temperature of the water to be added needs to be very close to the tank temperature to avoid temperature shock for the fish. (Speaking of which, is the tank heated? If not, does the room where the tank is have large temperature swings? This stresses the fish and can contribute to disease.)
Cycling and beneficial bacteria: In your filter media and gravel will develop a few different kinds of bacteria that convert fish wastes (toxic ammonia) into nitrite, which is also toxic, and then to nitrate, which is not as toxic and safe into the ~40ppm range. We then remove the nitrate with PWCs to keep the tank in balance and healthy. A cycled tank should have levels of ammonia and nitrite at 0ppm and nitrates up to 40ppm. Ammonia and nitrite are 'acceptable' up to .25-.5ppm; at .5ppm, a 25% water change is a good idea, and above .5ppm, a 50% change is a VERY good idea.
This process of developing bacteria takes time, and a product like Cycle, while claiming to develop this bacteria, doesn't really do much if anything. Aquarium salt is also not necessary, although it can 'soften the blow' of nitrite poisoning, so to speak.
You'd do fine with feeding the big fish once daily with only the amount of food that they will clean up in 2-3 minutes; not sure about the fry, probably smaller amounts more often than that, but you'll also need to be performing frequent PWCs on the 'maternity tank', especially if it's not filtered.