First and second picture have a pink gourami with a black spot on the bottom half of the body. this looks like a bacterial infection.
The third picture has 2 fish. One of the fish has black patches over its body and pink on the top of its face. The black patching is normally chemical burns caused by chlorine/ chloramine, or overdosed medication or plant fertiliser.
The pink area on the face is a sinus infection caused by bacteria, virus or protozoa.
Make sure the water quality is good and there is no ammonia or nitrite and the nitrate is less than 20ppm.
Do a 75% water change and gravel clean the substrate every day for a week.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.
Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it unless the flow is reduced.
See what the pet shop has for bacterial infections
I have actually seen that from over feeding. If your fish become constipated and food builds up in it's stomach. It can rot before being digested. Not saying that is what it is. I would treat as recommend above. But unfortunately might no be much that can be done.