in a tank or the ocean?
they will die
Ocean, salt water fish tank, a zoo exhibit, and aquarium.
When a fish dies in a tank, it can release harmful toxins into the water that can be harmful to other fish. To properly handle the situation, you should remove the dead fish from the tank as soon as possible using a net or scoop. It is important to also test the water quality and perform a partial water change to maintain a healthy environment for the remaining fish.
Then your filter is not on.
You can not. You should not put anything into your aquarium that you have found in the ocean. There are different bacteria and parasites in the ocean than found in your tank. In addition, the differences in PH balance and salinity are far greater. Plus the pressure of the water will different from the ocean to your tank. You not only risk the fish dying, but potentially killing off everything in your tank. There are quite a few beautiful species of reef fish available at your local saltwater fish store. Many are quite affordable and the expert at these stores can give you directions on how to acclimate your new fish.
assuming you have any fish left, test your water. do a 50% water change immediately. change your filter, it means there is something definitely wrong with your tank what are the details of your tank, size capacity, how many fish etcc
Salt Water Fish
It dies
I HAVENT AND MY FISH ARE STILL ALIVE (THE REMAINING ONES I MEAN)
Assuming the dirty fish tank has had fish and water in it, without doing various specialised water tests it is impossible to tell what is in it.
It might be unsafe to drink because fish food, fish scales, fish waste, and many different kinds of bacteria are in fish tank water.