You should do a water change after a fish dies in your tank, as this will help to minimize the risk of a spike in ammonia levels and other pollutants that can cause further harm to your fish.
Not necessarily if the dead fish is in the tank for a short period of time say 2 to 3 hours. But if it is in it for a long period of time then you should consider changing atleast 50% of the water. Remember never change 100% water since the beneficial bacteria in the water may die off.
A few of the steps you can take to save a dying fish after a water change is to ensure you stop feeding the fish immediately and also increase the oxygen content in the water. Aquarium salt has also been known to be a lifesaver in such situations.
When a sudden, large water change occurs, it causes such a drastic shift in the water parameters that the fish often cannot tolerate it and they die. 2 Those that do not die immediately are stressed and may succumb to disease over the next few weeks.
Completely replacing the water in the fish tank is a bad idea because it will remove beneficial bacteria that live in the tank and reset the nitrogen cycle, which could kill your fish. If you regularly clean your tank, doing a partial water change is the best option. Keep your fish's water clean, but not sterile.
Leaving it for a full seven days is best, as if others die within that time you'll know there's an underlying problem. Don't be tempted to restock and add lots of others, as this in itself can cause a water quality issue. Add a few fish each week and observe behaviour.
A partial water change should be completed when you find that a fish has died. It is recommended to do a 10% water change at a time to reduce stress on the remaining fish in your tank. If the ammonia levels remain high after doing a 10% change, or if you have a larger tank, you can complete a 20% partial water change.
It Could Damage Your Septic System or Plumbing
While your septic system and plumbing are designed for disposing of undesirable materials, dead fish are not on the list of flushable items. Septic systems are only meant to handle human waste, water and toilet paper.
Seafood expert Jon Rowley says no. He says the perfect time to cook and eat a fish is as much as five to six days after it died.
Once all sign of gill movement has stopped, placing the fish in the freezer until fully frozen will make double sure the fish is dead and can be disposed of safely. Clove oil, like the anaesthetics MS-222 and benzocaine hydrochloride, is effective in achieving euthanasia.
New Tank Syndrome is a term used to describe problems that occur due to the build-up of invisible, toxic compounds in an aquarium. It gets its name as the issue is most likely to occur when your filter is maturing when starting a new aquarium.
A dead fish, snail, shrimp or rotting plant can cause cloudiness in the water. Dead fish corpses break down very quickly in tropical fish tanks and if they are sizeable, or a few have died at the same time, the result can be polluted water.
Cycling with dead fish
By placing a small dead fish or prawn into your set up, you introduce ammonia for the bacteria to feed from. Doing this, you can see why it is a good idea to monitor fish health, as dead fish will need to be removed immediately, as they cause ammonia spikes.
Fish can live out of water for between ten minutes and two months, depending on the species.
If the fish keep dying, but the water is fine, this points to illnesses, old age, poor feeding habits, poor tank conditions, toxins from external sources, and prior problems with the fish.
Most fish are slightly denser than water, so sink immediately after death. However, like a drowned human, they become more buoyant over time as bacterial decomposition produces gases inside the body.
Tie it up in a bin bag and place it in the waste. You can bury fish in the garden although make sure you bury it deep enough to stop foxes digging it up, or cats. If your local fish store has asked to see the corpse keep it in the freezer as dead fish rot and smell very quickly.
Depending on how deep a fish was when it died, it might not rise to the surface, at least not until decomposition really sets in. Some fish never gain sufficient buoyancy to float and decay under the water. In case you were wondering, other dead animals (including people) also float after they start to decay.
Large water changes that include more than 60% water change, rinsing gravel, cleaning filter media lead to a complete, massive change in the water chemistry. Fishes when put in these new conditions, lead to temperature shock, stress, loss of appetite, and then death.
You should do a 25% water change every two to four weeks. There is no reason to remove the fish during the water change. Make sure you stir the gravel or use a gravel cleaner during the water change. When adding water back in to the aquarium, use Tetra AquaSafe® to remove the chlorine and chloramine.
But if you don't change the water often enough the nitrate level will rise, pH and KH will drop, and you'll get something called Old Tank Syndrome, whereby pH drops so low the biological filter stops working properly, your hardy fish just about survive it but newly purchased fish die within hours or days of being added ...