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You are here: myPetSmart.com > Pet Care Library > Ask An Expert > Answered Questions > I Had A Beloved Betta Fish A Week Ago That Passed Away Yest

I had a beloved Betta fish a week ago that passed away yesterday morning. I then...


I had a beloved Betta fish a week ago that passed away yesterday morning. I then got another Betta fish that same day and he passed today morning. I am doing everything required to keep the fish healthy and happy, but I am not understand why the fish are dying. My first fish, I fed a little bit twice a day in 12-hour increments, kept the hood light on for warmth and turned it off and night-time so the fish could sleep. I changed 50% of the water and he passed away when I placed him back in the tank. He was however a little sick from the petstore but was getting slowly better. The second fish was perfectly fine, swimming around very actively. However, he didn't respond to me as much as the first fish and preferred to find tight spaces to squeeze himself behind. What am I doing wrong?

You did not mention the water temperature, only that you kept the light on during the day for warmth, but turned it off at night. Bettas are tropical fish that require warm water, preferably 74-82 degrees Fahrenheit. They will die at temperatures below 64-68 degrees. What is the temperature in your aquarium?

It could also be a problem with the water quality. Are you using a dechlorinator when changing the water? What is the ammonia, nitrite, and nitrate level in your aquarium?

PetSmart offers free water testing, so you can take a water sample in to the store to have it tested. If you don't have an aquarium thermometer or heater, you can get that as well. We also have free care guides on keeping Bettas, and also on setting up aquariums and maintaining proper water quality. Ask a PetSmart associate for these informative brochures.


23 Jan 2011 3:27 pm

BeavisMom62 said:

I was also going to comment on temperature and water quality. I keep my bettas at a consistent 80 degrees. You need to use a heater obviously to keep the temp consistent. What sort of tank are you using? Bettas optimally should be kept in at least 5 gal of water. Betta vases and other decorative "tanks" are too small. A betta would be healthier in a larger tank with a filter so that you can cycle the tank, which through the actions of good bacteria, help to keep the water healthy. You cannot cycle a small tank because there generally aren't filters which are adequate for these tanks.

I would recommend that you have a 5 gal tank with a heater, thermometer and filter. Make sure you use a dechlorinator in your water. Do water tests (preferably using the API master test kit, not test strips) and partial water changes weekly.

Also, it is possible that, if it wasn't a water quality issue which killed your first betta, that he may have had an illness which was present in the water when you added the second fish.

Generally, if a fish dies after a water change it is because the temperature of the new water was different than the water in the tank or you didn't use a dechlorinator in the new water. Occasionally, there will be a difference in the ph from the tap compared to the ph in the tank. If the tap water from your tap drops over time, then make sure to leave your water sit out for a few days before you add it to the tank. Then check the ph to make sure they are the same or at least very close. I've lost fish from all three of these scenarios.

Fish keeping is a constant learning experience. Unfortunately, fish do die as we learn, but eventually with research, time and trial and error you will become an expert.

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