Looks like a plant that started to flower and then revegged.
Is it indoor grow ? Give all details of the grow.
My first thought as well. 
Mine as well. Could also be genetics all of the leaves look a little funky
Yes it’s indoor. And yes they were in flower, and they were too small and i put the back in revegged. Is that a problem? What should i do with them?
@Max123. That is why your leaves are curling and only singles.
It will change back and veg after a bit but usually a reveg takes a little longer to get reestablished.
18/6 light on off schedule should get things back on the right track.
I have this fly, i am so angry, they don’t want to dye🤬… i saw they are on the soil, do i need to change the soil? I try with 2 different bug killer… And the leaves are really bad.
It’s just because of the fly? Do they have another deficit? I am on my first grow… but it’s a little difficult 
Ok. Thank you
Looks like a fungus gnat.
Some diatomaceous earth sprinkled over the soil will slow them down.
Also some yellow sticky cards will allow you to monitor the progression.
We still need to know what you’re growing in
for soil specifically what soil.
Light , temps , water and feeding , how often.
There is a support ticket for this.
Gimme a min and I’ll see if I can find it. 
COPY/PASTE the below list into your forum post.
Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so; Or post
NA (non applicable)
- What strain, Seed bank, or bag seed
- Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF
- Vessels: Pots, Grow beds, Buckets, Troths
- PH of Water, Solution, runoff (if Applicable)
- PPM/TDS or EC of nutrient solution if applicable
- Indoor or Outdoor
- Light system
- Temps; Day, Night
- Humidity; Day, Night
- Ventilation system; Yes, No, Size
- AC, Humidifier, De-humidifier,
- Co2; Yes, No
Always try to upload a clear picture of any issues you may have to allow the community to assist you.
Add anything else you feel would help us give you a most informed answer should be included. Feel free to elaborate, but short and to the point questions and facts will help us help you in a more efficient manner 
Here we go.
- the strain, northern light
- organic soil…flower soil… i don’t really know what tipe
- vessels: pots
- ph water…i don’t know yet, because the ph meter didn’t arrive yet, i have some problems with shipping…
- nutrient solution, i have some tablets i put them in water. And one time in week.
-indoor
-light 600 - temp. Day 28-30°, night min 20°
-humidity day 50-60, night 30-40
-ventilation, fan 20". All the stuff are in my wardrobe, and over the day i open the door, to go some fresh air inside. - i have some small de-humidifier
I hope this can help you.
I am sorry for my english, is not my first language…
@Max123. Understood on the language barrier. 
We’ll get through this.
You really should have the ph and tds meters so that you can get a better idea of what you’re putting into your plant.
What tablets are you using to feed with ?
You really should have cannabis specific nutrients and soil for growing.
A quick search online will give you some choices of what’s available in your area.
Fox farms or pro mix are good choices.
How often are you watering ?
Overwatering will help the gnats breed and cut off oxygen to the roots.
Cannabis needs a wet to dry cycle to promote good growth.
Only water when pots get light and you can stick your finger in the soil to the second knuckle and feel only damp at that depth.
Lift your pot just after watering to get an idea of the weight. Then wait till it’s noticeably lighter before watering again.
@Myfriendis410 can add to this.
He’ll see this and stop in in a bit
You’re off to a good start and with a few tweaks can get this girl to the finish line.
And welcome to ILGM.
I put 2 times in week water, yes i know with the ph…it’s my fault, i didn’t know from beginning…
And the tablets are these
All good advice. @Oldguy has you covered.
What bug killers? Toxic shit from chemical companies? I hope not.
Fungus gnats are an indication that your top soil is staying too wet as they feed on the green growth that happens when you water too much. They will lay eggs in soil and they hatch into larvae that eat compost in soil and they can end up munching on your roots. Much safer ways to deal with them than bug sprays as that will only mess up your beneficial soil critters (kill them too) and I’m sure you don’t want it negatively affecting your plant and then when you consume the plant those chemicals get into you too.
Search on this site about fungus gnats … lots of info to read/learn
Thank you everybody, i will see in a coupple of days how they will be after i will do what you told me.