Can you post some pictures and a short 60 second video of the remaining fish, and pics of the dead fish if you still have them?
Also post a picture of the tank.
Have you tested the tank water to make sure the fish aren't dying from poor water quality?
How often do you do water changes on that tank?
How much water do you change on it?
Do you dechlorinate the new water before adding it to the tank?
What fish are in the tank?
Did you add anything to the tank in the 2 weeks before they started dying?
a better video for you, that’s just after I’ve put food in