Darktideanswered grow question 4 years ago Fungas Gnats are caused by overwatering.
Your plants soil looks very wet.
The first step is to let the soil dry out.
In your next watering you can use Hydrogen Peroxide to treat.
I had great luck using 1 part 3% Hydrogen Peroxide to 4 parts water. You can use this mixture to spritz the the soil, filter spray amd water your plants with. I used this treatment every second watering for about 6 weeks along with yellow sticky traps.
Then no treatments and monitor. If no gnats, watch as about 2 weeks later some of the left over eggs may rehatch and require a couple more treatments.
A good rule of thumb is to check the spoil about 2 inches away from the stem in a few spots by sticking your finger in to the first knuckle and not water until you feel that the soil is dry all the way to the knuckle.
In a side note I found it really helpful to pick up a super cheap moisture meter for those times when I was not quite sure on the moisture.