That is sure not normal Danio behavior! If you would like some help we need more info about the situation. Can you answer these questions for us? Thanks.
1. Size of tank?
3 Gallon Tank
2. Water parameters
d. pH, KH and GH?
e. Test kit?
The store didnt have any test strips!
Out of thermometers... (Im not kidding at all)
4. FW (fresh water) or BW (brackish)?
5. How long the aquarium has been set up?
6. What fish do you have? How many are in your tank? How big are they? How long have you had them?
Danios, 2, 1 inch, 3 weeks
7. Were the fish placed under quarantine period (minus the first batch from the point wherein the tank is ready to accommodate the inhabitants)?
8. a. Any live plants? Fake plants?
b. Sand, gravel, barebottom?
c. Rocks, woods, fancy decors? Any hollow decors?
9. a. Filtration?
Not as of right now
10. a. Lighting schedule? What lights are used?
Normal lightening schedule.
b. Any sunlight exposure? How long?
No direct sunlight
11. a. Water change schedule?
b. Volume of water changed?
c. Well water, tap water, RO water?
d. Water conditioner used?
e. Frequency of gravel/sand (if any) vacuumed?
Do not vacuum
How often are they fed?
Once per day
13. a. Any abnormal signs/symptoms?
b. Appearance of poop?
c. Appearance of gills?
14. a. Have you treated your fish ahead of diagnosis?
b. What meds were used?
15. Insert photos of fish in question and full tank shot if necessary.