I had my betta about 10 months ago. He was really sensitive to water, and a lot of stuff would give him fin rot (Dannon spring water, ozarka, etc.). However, he always recovered pretty nicely. I was always able to catch fin rot within 24 hours of the water change to treat it.

I was treating him for fin rot this week (he was doing really well), and last night I cleaned his tank, put in his medicine, and fed him. I did not overdose. He seemed fine. As I was going to bed, I noticed he seemed to be floating at the top, he wasn't dead, but his front fins were clamed to side and he was just floating. When I thought he was dead, I put him in a cup and he moved his front fins again, but when I put him back in the tank he started floating again. About 30 minutes later, he tried to swim to the bottom of the tank, but just kept rising to the top kind of upside down. I went online and started researching things I could do to help him, and then he started swimming around erratically and coughing up his food. Soon after that, he started to tip sideways, and he had trouble staying afloat. He was also at the top gasping for air. Then he made a splash and flipped over and nosedived down into the tank. At this point, I removed him from the tank but he continued to be in the upside down position and was breathing heavily and slowly. He had never had swim bladder before, and he died within 10 minutes of the first time he seemed to lose his balance. There isn't any discoloration that I can see, except that his underbelly seems a bit darker now that he is dead.

I really loved my betta and tried to take good care of him. I was up all night crying. What did I do wrong?

I looked at my Betta again and now I see that he is starting to become discolored, but he has been dead for almost 10 hours, so that may be natural, right?

Another detail I remember now: when I first noticed he was not doing well, his front fins (the shortest ones) looked white and skeleton-like.

Thanks for any help.

What size aquarium was he in, and was it filtered, and cycled?

Please supply your water readings (Ammonia, Nitrite, Nitrate, and pH if you have it).

Bettas (or any fish) should not regularly get fin rot. That is a sign of poor water quality. In addition, fish of any kind should not have bottled "spring" or distilled water as all the minerals and nutrients are taken out of the water... fish cannot survive (longterm) in this environment. :(

In addition to the previous poster's questions, I would add these questions.

When you did the water change, did you change it all? 100% water changes are very shocking for a fish. The water chemistry, temperature, and conditions may have been different than what was in there before. What water did you use for the change? What was the name of the medicine that you used? Some medications can be toxic even at normal dosages if the water is soft for example.

Fin rot is a bacterial problem that usually occurs because of the stress of poor water quality. Treatment might include aquarium salt, MelaFix, and antibiotics as well as plenty of room in an aquarium that gets routine water changes (not too much or too little) and maintenance.

- He was in a small (about 1 gallon) plastic tank, and it was not filtered
- I don't have any water readings. He was my first and only fish, sorry.
- I did not use distilled water. The spring water I used was bought at a health food store and had nutrients and oxygen added to it.
- He has had fin rot three times since I got him (about 10 months) The first time, I was out of town for 3 days and the person that was taking care of him put too much food in his tank and it rotted and caused the water to get icky. The second time was when I used dannon spring water, but it was about a week after his first battle with fin rot, and the third was 3 days ago. What type of water should I use in the future?

- I did a 100% water change because he had fin rot, and the water was the same temperature. Normally I do about a 75% water change.
- I used Mardel to treat his fin rot. I had used it in the past to treat him.
- I changed the water in his tank about once every 5 days.

The large water change was probably a shock for him. Avoid changing more than 50% at one time except in emergencies. It's ok to change 50% every day until things get better. A 1 gallon is larger than some people keep bettas in so changing 50% a week should have been ok. It's usually ok to use spring water but be consistent in the type that you use. My only concern would be its oxygen levels but that can be fixed with aeration. For a betta, it's less important since he can get oxygen from the air if he has to. Which of the Mardel products did you use for fin rot? Maracyn? If you want to try another betta, the 1 gallon tank is large enough to put in a very small filter or even just an air stone (not really so he can breathe since he can use atmospheric oxygen but so the water doesn't stagnate). While bettas like slow moving water, a little current will keep the water from stagnating, and the filter will help improve the water quality, reducing the bad bacteria in the water that cause fin rot too. If you get a larger tank, then real filtration would go a long way to keeping a healthy betta.

Even though it was hours after the water change? I used the same water and it was the same temperature. Why would it make him cough up food and tip over? Even when dead, he still was straight upside down in the water. What caused that? Thanks for your help!

My guess is it had something to do with the size of container he was in. I (personally) would never keep fish in anything smaller than 10 gallons, but that is me. I would also guess that this container was not cycled either, which is very important.

I do not believe he died from just an excess of a water change. Many times you have to do 60-80% in such small containers, so that should not have caused him to "keel over". If the pH was different, or the temp was different that would be a different matter though.