Should I be worried about dropsy bacteria in my tank?

[Glitterous]

I had a beautiful male betta in a tank here in my office. He was perfectly healthy for about a year, and then suddenly he got dropsy and died. I was on my honeymoon right before then, so I'm guessing something happened while I was gone to give him whatever caused the dropsy.

It was a planted tank, so I took everything out, soaked it in a solution of 10% listerine and water, then washed everything out very well. I got a new, better filter and I set the tank back up and let it cycle for three weeks. I put a sponge that I keep in the filter of my main tank at home in the filter of this one to encourage healthy microbe growth. I have never had any problems with my tank at home.

After three weeks, I added three new betta ladies and an otto. Immediately one of the girls was acting strange. She didn't explore the tank or try to establish dominance. She floated at the top of the tank and would not eat. I was worried she might be ill, but I also considered that she could be shy and was trying to avoid the crazy hijinks of the other new fish. I left her in the tank over the weekend.

When I came in this morning, she had dropsy and was sitting on the bottom of the tank. I immediately removed her and put her in a hospital tank, but I don't have a great deal of hope for her. However, I do have a couple of questions now.

1) Should I do anything, other than watching and praying, for the rest of my fish in my community tank? I know you're not supposed to give medicine to sick fish, but is there any preventaive measure I should take? I've done a 10% water change already.

2) Is whatever is causing dropsy in my tank, or is dropsy common enough that this girl could have brought it with her from the pet store? If it is something in my tank, how should I handle it (ie sterilizing a planted, stocked tank)?

 

[jsoong]

I suspect that the betta is sick to start with.

You have already did a tank tear down after the the male betta died. It is unlikely that anything bad is left after 3 weeks. <I am not familiar with using listerine in fish tank, but I suppose it would be OK after you rinse it out really well.>

I can't think of anything more to do, except keep an eye on the remaining fish & make sure the water parameters are kept perfect.

 

[An t-iasg]

Hi Glitterous and welcome!

I'm sorry to hear about your male betta. I wouldn't assume anything "happened" while you were gone to cause the dropsy. I have had many bettas and about half of them died from dropsy after they had a nice long (and otherwise healthy) life.

I also have planted tanks and I don't tear them down after a fish dies. I tend to leave them fallow - empty of fish - for a month or so. I still do water changes during that time. Any disease-causing bacteria will most likely die without a host and the tank will then be ready for new fish.

Dropsy isn't really a disease itself, but it's a symptom that something is wrong. It may be a tumor, or kidney or other organ failure. There are other causes besides a bacterial infection, and it's very hard to tell. Giving medicine to sick fish is ok when you are reasonably sure that you know the cause of the illness and give the right kind of meds.

I would also think that the new betta was ill when you got her. You can try some epsom salt in the water - 1/8 to 1/4 teaspoon per gallon. Start off with 1/8 teaspoon and gradually increase if you see no results. Leave her in this water for a day or two, and then do small water changes to gradually remove the salt. Be prepared to do a water change before the end of the two days if you see any signs of stress. For the remaining fish in the tank, I would agree with jsoong and just keep an eye out - maybe do a few extra water changes to make sure the water is pristine. I wouldn't assume that the tank needs to be sterilized again. We don't know if the new betta has brought in a bacterial infection, so just be watchful and a few extra water changes can't hurt.

 

[Glitterous]

Thanks for the condolences and advice.

I've been doing very frequent water changes and things are... well, they're okay. I took the betta with dropsy back to the pet shop because I couldn't stand to watch her die slowly; I know that was cowardly on my part. I lost another betta who was seemingly healthy just the day before (she was pretty well picked over by the time I "fished" her out, so I can't say what was wrong, other than she was a cellophane and had a large green spot showing through on one side of her tummy. Internal bleeding?) I don't think it was dropsy because she didn't look swollen.

Hopefully it's just cheap stock, considering I purchased from Petsmart. We'll see what happens!

 

[Zagz]

Sorry for your losses. Did you add an ammonia source to keep your cycle going that 3 weeks? If not any beneficial bacteria you had in your sponge would have died off. Any ammonia or nitrite in the water would have affected a sick fish far faster than a healthy fish.