Can someone please give me a concrete answer as to why fishes die after a full water change of their tank?

Question

Thanks! :)

Answer 1

There are a few causes actually. Shock from being taken out of what they're used to and dropped into purely clean water, the fishes system cannot handle it.

Another is being dumped in a completely different environment because the water was completely changed. Doing this kills off the good bacteria colonies in your water causing the tank to go into a cycle. This causes the toxins in the water to build and battle and it can damage your fish, the bad bacteria chews on them and literally causes them damage.



This is one of the main reasons people usually cycle their tank before adding fish. They are unable to survive in waters that aren't meant for them. Too many bacterias and toxins fighting it out. Although some fish can handle a fish-in cycle, it's not good for them for the reasons named above, it harms them because the toxins chew on them inside and out. There also isn't proper oxygen in the water.



In other words the main reason is because of the toxins and bacterial battles in the water. Some types are good for the fish, others will feed off of, poison and kill the fish, or just plain destroy their immune systems so the bad bacteria can infiltrate the fishes systems and kill them. Fully cleaning the tank destroys the good bacteria system in the tank that made it a stable environment for the fish to live in and causes everything to battle, die and reclaim. It'd be like trying to build a house in the middle of a war-zone and hoping you don't get bombed or raided by both sides.

Answer 2

1. The entire environment is change All the water. It like taking a humane from a class room and beaming it up to the top of mount everast. Shocking right? And most people who change 100% of the water do not bother to float and acclimate the fish to the new water.



2. when you remove the fish, and it is very very scary. And can cause shock.



3. chasing a fish with a net, catching it, pulling it out of the water and handling a fish is enough to cause shock. But also every time you touch a fish, part of its slime coat is damaged "fishy immune system"



4. Fish are cold blooded. when the water temperature changes, their entire body and blood temperature changes. Body functions change, everything is effected.



5. changing all the water and the envirenment in the tank bot only stresses, the fish, but also the healthy bacteria keeping the tank cycled. If you kill to much of it, your tank needs to re-cycle. And now the water is full of burning nirtite and ammonia, and the Ph may bounce.



4.

Answer 3

I regularly perform 100% water changes and don't loose fish. Old water only brings death, new water brings life.



The reason for the issues is people do not take proper precautions. In order for deaths to result from large water changes there has to be a significant water chemistry or temperature difference between the new water and old water. The most common causes of water chemistry differences are actually caused by us. Either we refill without proper dechlorination, we have substrate in the tank (such as crushed coral or argonite) or limestone rocks (such as Texas Holey Rock) that leaches calcium and magnesium into the water, increasing hardness and TDS values. When we then perform a water change the TDS values of the replacement water are much lower than the tank water and this causes osmotic shock and subsequent death in the fish.



Another cause is Old Tank Syndrome (OTS). OTS occurs when we are not diligent enough in our water changes. Bacterial processes in our tank (the nitrogen cycle) release acids that erode away the carbonate buffer (KH). Once eroded, the pH crashes and with a pH crash nitrifying bacteria (the bacteria that removes ammonia and nitrite) go dormant and ammonia starts building up in the aquarium. But with a low pH the ammonia is in a non-toxic form (ammonium) so it does not affect the fish. Then we come along, unknowingly, and perform a water change. The new water is of a much higher pH and with the subsequent pH increase in the tank the ammonium is converted back to ammonia and the fish die.



These are some of the most common reasons, all easily avoided provided you know how to prevent them.



A couple of articles related to this subject can be found here:

http://www.oscarfish.com/article-home/water/73-myths-of-ph-shock.html



http://www.oscarfish.com/article-home/water/74-realities-of-ph-shock.html

Answer 4

When you don't let the new tank water sit for 24 hours or use fish drops the tap water can kill the fish.

Answer 5

usually the cause is temperature or pH shock.



pretty simple really, just never change more than about 25% of the water at any one cleaning. It's basic aquarium care.



note: there are situations where larger water changes are possible, but this requires understanding the water chemistry and obeying certain "rules"

Answer 6

It matters what kind of fish your talking about. For some fish, the change might be too much for them and they can't handle it, or the water temperature might not be right.

Answer 7

General biology. You are taking this fish and putting them into a more hypotonic environment

Answer 8

They lose too many salts in their body and it kills them.



General biology. You are taking this fish and putting them into a more hypotonic environment.