Help! My molly is lying on the gravel, gasping for breath

Tank

What is the water volume of the tank? 20g
How long has the tank been running? Since September 2018
Does it have a filter? Yes
Does it have a heater? Yes
What is the water temperature? 78f
What is the entire stocking of this tank? (Please list all fish and inverts.) 8 adult mollies and platys, 8 itsy bitsy baby platys (that will be moved when they are bigger), two zebra nerites

Maintenance
How often do you change the water? Weekly (tomorrow, Saturday, is water change day)
How much of the water do you change? 30%
What do you use to treat your water? Aquasafe
Do you vacuum the substrate or just the water? Just the water

*Parameters - Very Important
Did you cycle your tank before adding fish? Yes
What do you use to test the water? API liquid test kit
What are your parameters? We need to know the exact numbers, not just “fine” or “safe”.

Ammonia: 0.25 ppm
Nitrite: 0 ppm
Nitrate: 5.0 ppm
pH: 8.2

Feeding
How often do you feed your fish? twice daily
How much do you feed your fish? a ground up pinch of flakes
What brand of food do you feed your fish? Aqueon Tropical Flakes
Do you feed frozen or freeze-dried foods? No

Illness & Symptoms
How long have you had this fish? Since September 2018
How long ago did you first notice these symptoms? Today
In a few words, can you explain the symptoms? My male molly is lying on the gravel, gasping for breath
Have you started any treatment for the illness? no
Was your fish physically ill or injured upon purchase? no
How has its behavior and appearance changed, if at all? Appearance is actually good

Explain your emergency situation in detail. (Please give a clear explanation of what is going on, include details from the beginning of the illness leading up to now) My male molly is lying on the gravel, gasping for breath. I noticed this when I was feeding them breakfast. He did eat, but has spent every other minute today on the gravel, gasping.

Can you get a picture of your fish and post it for us, please? Temp to a little warm for guppies. I’d lower it to about 74F. I’d also do a larger water change, like 70% in case it’s a water issue. Let’s see that pic.

Here he is, my big boy.

Is he possibly constipated or bloated? I would do the w/c and try feeding him a shelled pea that has been boiled in water for a minute to make it soft. That will help if he is constipated. Don’t feed him anything else but the pea for 24 - 48 hours and see if the issue resolves. Good luck! Keep us posted.