Disinfecting tank from fin rot bacteria

[Sandip]

Hello
I am in a very complicated situation here. Don't understand how to proceed so looking for a step by step guidance.


I have a 80 L planted tank with almost 19 fishes, mixed varieties and 3 mystery snails.



The filter is a mini canister filter with around 500 L/H capacity. Bio media is Seachem Matrix. Also I use filter flush, activated carbon and sponge inside it.



The water parameters are as follows


Temp: 26 C
pH : 7.0
Ammonia & Nitrite : 0 ppm
Nitrate : < 20 ppm


The problem is, there is some kind of fin rot bacteria there. When I add fish to the tank in 1-2 days many of the fish get affected by it and start to die. it happens to almost any kind of fish I add. The existing 19 fishes have immune system strong enough to survive and they are happy and healthy also growing in size.



The tank with the fishes are running nice for more than 3 months now but whenever I am adding new fish in 1-2 days they get fin rot problem and start to die. I saw few dead fish with almost no fins but most of the dead fish get eaten in the night by other fishes and snails, I find no sign of them. I added an otocinclus few days ago, He is alive moving around but the rear fins are kind of gone.



Regular water changes, cleaning everything in the tank even changing the full substrate did not help much. Only delayed the fin rot for few days.


I want to disinfect the whole tank so that I can add some guppies and more otocinclus etc.



I live in Brazil so we don't have all the things that you can get in US or anywhere. We have something called "Labcon Bactor" which contains neomycin. Here everyone uses it for curing the fish from fin rot. The indicated dose is for 7 days. But in my case I am worried that if I add it to the tank I will lose the beneficial bacteria in my filter and lose the nitrogen cycle too.



I don't understand how can I proceed so the tank can be disinfected and the cycle will not get affected. I will be very grateful if someone can advice me a step by step procedure.


Thanks

[Aiken Drum]

Anything that is genuinely antibiotic can easily kill off beneficial bacteria and your cycle. It cant tell the difference between bacteria you want to kill and bacteria you want to preserve. This is why you try and medicate in quarantine rather than your display tank.

Could you get a tote bucket and move your filter to that, dose with ammonia to keep the BB alive while you disinfect the main tank. Get an airstone in the main tank to keep it oxygenated and plenty of water changes and prime to keep your fish alive while its not being filtered?

[Sandip]

Hi
Thanks for the reply.
That was the idea I had too but was also expecting some other way, if possible.


Anyways there are 3 questions more :



1) Can the fishes who are immune against this bacteria carry the bacteria if I transfer them to another tank (Just the fish not any water or anything from the infected tank) ?

2) The filter media and water inside the filter can have the bacteria in it too. If I put it back after 7 days of treatment, can the bacteria grow back in the disinfected tank again ?


3) If the tank left untreated for a longer period of time (5-6 months) only with the existing fishes can the bacteria get wiped out automatically, I mean because of lack of food or something ?


Thanks

[Aiken Drum]

Im not convinced that you have healthy fish already in the tank that are immune to some bacteria that newer, also healthy, fish have no immunity to. That just seems unlikely. I feel its much more likely that the newer fish you are getting are just already compromised when you get them, either they are already infected with this fin rot or they have other health issues and are therefore more prone to secondary infection. If there is a bacterial infection serious enough to infect otherwise healthy fish it wouldnt discriminate between the healthy fish you already have and new healthy fish.

Quarantine new fish for 2 or 3 weeks. If they are fine during QT but succumb to fin rot after then being introduced into your main tank you can conclude its something in your main tank.

In answer to your questions though.

1. Yes they can. Low levels of bacteria will always be present, healthy fish are more likely to fight off infection, already unhealthy fish are more likely to pick up secondary infections.

2. Yes it can. Even if you manage to kill off all the bacteria, it will find its way back in either through the atmosphere or when you introduce new fish. You will never entirely eradicate bacteria from the tank as it will always find a way back in at low levels. Again, healthy fish can fight off infection, unhealthy fish are more likely to pick up secondary infections.

3. No. This might work for parasites which have no way of being introduced except for you accidently introducing it yourself, but bacteria are always going to be present even if at low levels.

[Sandip]

Hello
Thanks for all the explanation.



I normally trust on the fish store, as I know the protocol they follow also I never buy a fish which is not in their aquarium for less than a month. The employee is my friend. I and my other friends bought many fishes from the store and never had any problem. That's why I don't even have a QT tank.

I would like to explain the case of the otocinclus. I bought 2 of them. I put both of them in a tank where I have only female betas. Both of them were there for more than a month. Everything was fine. Later on I took one of them and put in the 80L tank. All the current fishes in the 80L tank are healthy, no fin rot at all. Only 2 days after I found the rear fin of the otocinclus is almost gone. He is alive, eating a lot and moving around the tank with this missing fin. The other otocinclus in beta tank is healthy and happy, no fin rot at all. From this and scenarios like this I concluded that the tank has fin rot bacteria and the fishes are immune to it. I don't know what else to conclude.



But anyway, as I saw from your answers, the only way to get rid of this bacteria is to lose the cycle. I am not having a mental condition to make these fishes suffer through the cycling process also not having much time to spare. So I will let the tank run as it is. May be I will treat the otocinclus with the antibiotics separately, not sure.


By the way thanks for all the information.
I hope it may help someone else too.

[animalia]

If it was my tank, I would add Melafix which cures fin/rot. Always put new fish into a quarantine tank. Don't restart your tank. Melafix will fix the problem. If you recycle now the fish will not cope. you can also add stress coats you can get them at most fish shops or order them online. The slime added to the tank will give them extra immunity to any diseases. Hope that helps.

[animalia]

https://www.google.com/search?q=new+...nt=products-cc

[Sandip]

Hello

Thanks a lot for trying to help .

As I told above, I live in Brazil. We don't have all the products as you people get in USA. If I buy it online, it's always imported and costs at least 3 times more than the actual price because of the import taxes. Just to give you an idea, how much a 237 ml Melafix costs here, is almost double the price of all my fishes together. If I just donate all the fish to some fish store (they will quarantine them for a month as a protocol), bleach the tank and filter and start everything again it will be much cheaper.



But as I said the fishes have no symptom of fin rot I think I can leave the tank as it is. Just wanted to add some guppies but they never survived this bacteria. But it's ok. I have to accept it. May be I will make a small tank only for guppies and some shrimps later on.

There is another option too, I can put some Seachem Martix in my betta tank for 2-3 weeks and as the bacteria develops on it, I can use that in my 80 L tank as seed for new bacteria after treating the tank with neomycin.



Let's see. I need to find some time for this.


Thanks a lot for all the responses.

It really helps to see things from a different prospective.