fish tank water

Question
I have lived in my current home for 15 years and had a water softner installed shortly after moving in. I decided to set up an aquarium after not having fish for many years. I never had any problem with my fish (I have had fish for over 30 years)and now whenever I bring new ones home, they die within 48 hours. I was wondering, since I didn't have the water softening apparatus in other homes, if that has any effect on the water in the tank. I have three angel fish that are over 3 years old and several rasbora. I have been involved with fish most of my life---raising and breeding. Don't know why the water is "suddenly" toxic to the newly introduced fish. The local pet store tested my water and told me to change out about 1/4 of the water every two weeks. If the softner water has any effect, this, obviously, would not be beneficial. Ph is extremely low. Tank is filtered regularly and filter changed. Tank is clear except for slight algae on side of tank that gets some sunlight, but not an excessive amount of algae. What would be your recommendations? Why am I suddenly a failure at this lifetime hobby?

Answer
Hi Nancy;

It could be pH shock and like you said, if the softener is responsible for the low pH, water changes aren't going to have any effect on it. Or, it could be the new fish are dying from osmotic shock. Water softeners that use salt to recharge the ion resin can allow a little bit of salt to get in to the tap water. Yours may be doing that so your fish are already used to it and the new fish aren't, causing death from osmotic shock. Osmotic shock can happen to freshwater fish that are too quickly introduced to water that has a different salt or mineral content than what they are accustomed to.

Very low pH can be dangerous and cause a collapse of the beneficial bacteria in your tank's system so it might be best to try to stabilize it naturally whether you ever get new fish again or not. Avoid using chemicals to alter it though. They can cause deadly fluctuations and often the pH is right back where it was in a few hours. I would start changing water with unsoftened water instead. Many water softener systems have a bypass valve so the water softener isn't being used when you choose to divert it. Or, most outdoor spigots aren't on the softener so you could start using some of that water along with the softened water. Maybe 1/2 and 1/2. Make your once a week water changes for a few weeks that way so it slowly changes and maybe it will help new fish survive. Just be sure that the water you add to your tank is the same temperature as the old water, wherever it comes from.

There is a way of acclimating the new fish that may help new ones survive when you have had trouble in the past. When you buy new fish, acclimate them to your tank water by slowly pouring small amounts of the tank water into the transport bag as they float in your tank. This process should take 2 or 3 hours at least so the fish need enough water and air. Add maybe 1/4 to 1/2 cup of tank water to the bag every 15 minutes or so. These water additions will not only help them get used to the new water chemistry but will also give them additional oxygen as they wait. Re-seal the bag between water additions, leaving a big air bubble. When they have been acclimating for a couple of hours, gently net them from the bag to release them into the tank and throw the nasty old transport bag water away. I've used this acclimation method many times and it seems to work pretty well. You really should get the tank pH up to a reasonable level first though. It will give your new ones a much better chance and hopefully avoid disaster in the future.

Good luck!

At Your Service;
Chris Robbins