How can I clean and disinfect a tank that had a kill off? - The Planted Tank Forum
 
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post #1 of 15 (permalink) Old 02-02-2015, 01:23 PM Thread Starter
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How can I clean and disinfect a tank that had a kill off?

I have a 10 gallon, fairly heavily planted tank that housed just a betta until last week. Thursday, we went out and got 3 harlequin rasboras, after proper acclimation and introduction to the tank, all the inhabitants seemed to be doing well. I didn't use a QT for the new fish, lesson learned....moving on.

A day later, Friday, we decided to get 2 more rasboras. Brought them home, started acclimating them to the tank water, and while doing that I performed a 20% water change. After introducing the last two rasboras to the tank my betta almost immediately started showing signs of illness (lethagic, shallow breathing, laying sideways on the bottom of the tank).

The betta got moved to a 1 gallon container treating him with epsom salt as it looked as if 1 of his eyes was swollen. Today will be his 4th day in the QT with epsom salt and he's being much more active and curious about his new surrounds, he's also eating well.

On to the rasboras in the planted 10 gallon. We lost the first 2 rasboras with no signs of any kind of illness. The 3rd rasbora swam upside down for about 5 minutes before settling to the bottom and dying. The 4th has a single little white dot protruding from his bottom lip, he died last night shortly after the upside down swimming 3rd. The 5th and final rasbora made it trhough the night but he's mostly staying put in the corner of the tank near the top, and not eating (hasn't ate since Friday).

My question is, how can I ensure that my tank isn't infected with something that killed off almost all of the rasboras (especially since there weren't any signs of illness for the most part)? What steps should I take with cleaning the 10 gallon before adding my betta back to his tank?

I assume it would be best to donate the final rasbora to the pet store as they won't do good by themselves anyways?

Sorry for the long winded post, I'd really like to keep the 10 gallon tank up and healthy for my betta as I won't try adding anything else to his tank after this disaster.
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post #2 of 15 (permalink) Old 02-02-2015, 01:28 PM
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Don't give it back to the lfs if it's potentially infected with something. You may have overloaded the bio filter adding 5 fish so quickly, or someone had something. If you want to clean it I'd use bleach to disinfect, then rinse rinse rinse, dechlorinate dechlorinate dechlorinate
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post #3 of 15 (permalink) Old 02-02-2015, 01:29 PM
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Without knowing what the issue is(water quality,or disease)I would do a LARGE water change on the 10 after the last Harley is out and stay fishless if possible for a week or two.
Some issues could survive through this,but several infections NEED a fish to "host" and survive.
Without medicating or tearing down this might be the easiest option.
Make sure to keep up on waterchanges for betta in the 1g.Does he have heat?
They prefer over 80 and clean water.

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post #4 of 15 (permalink) Old 02-02-2015, 01:34 PM
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Simplest: Many diseases will die out without a host. If the Betta is OK where he is, just run the 10 with NO fish for a few weeks or so. Keep the beneficial bacteria alive with ammonia or fish food.

A little more complex: If you can treat the tank just like there is a sick fish in there, perhaps with antibiotics then this MIGHT kill off whatever killed the fish. But you do not know. Without a fish in there to show you by recovering, you do not know if you have chosen the right medicine.
You could try something pretty broad based and mild like Melafix and Pimafix. Make sure these are out of the water before you put the Betta back. These are not good for fish with labyrinth organs.

Most severe: Tear apart everything, throw away anything that cannot be treated and treat everything else according to what it can handle. If you try multiple treatments make sure you thoroughly rinse everything between treatments. Some of these could be tried without tearing everything apart. Assume these will kill the biofilter, and re-cycle the tank:
1 part bleach: 20 parts water for a few seconds to a minute (plants might survive, but so might disease organisms)
Stronger bleach: Will kill plants.
H2O2: Research the optimum strength. (See a thread in the algae forum called One-Two Punch)
Excel: See H2O2. Do the 1-2 punch.
Potassium permanganate: Follow all label directions.
Other: There are probably more ways to deal with this, but without knowing what it really is any treatment is just a shot in the dark.

Do whatever treatment you want, then buy some Harleys from a trusted source and add them before adding the Betta back, as guinea pigs.
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post #5 of 15 (permalink) Old 02-02-2015, 01:36 PM Thread Starter
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Quote:
Originally Posted by Dead2fall View Post
Don't give it back to the lfs if it's potentially infected with something. You may have overloaded the bio filter adding 5 fish so quickly, or someone had something. If you want to clean it I'd use bleach to disinfect, then rinse rinse rinse, dechlorinate dechlorinate dechlorinate
Bleach even the plants, sand, decorations?

Bump:
Quote:
Originally Posted by Coralbandit View Post
Without knowing what the issue is(water quality,or disease)I would do a LARGE water change on the 10 after the last Harley is out and stay fishless if possible for a week or two.
Some issues could survive through this,but several infections NEED a fish to "host" and survive.
Without medicating or tearing down this might be the easiest option.
Make sure to keep up on waterchanges for betta in the 1g.Does he have heat?
They prefer over 80 and clean water.
I've been doing 25-50% water changes daily since the first fish died.

As for the betta in his 1 gallon, he gets a 100% water change daily, and there is a heater in there (keeps it ~77 consistently).
post #6 of 15 (permalink) Old 02-02-2015, 01:40 PM
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Originally Posted by [email protected] View Post
Bleach even the plants, sand, decorations?

Bump:

I've been doing 25-50% water changes daily since the first fish died.

As for the betta in his 1 gallon, he gets a 100% water change daily, and there is a heater in there (keeps it ~77 consistently).
Everything but the plants could take full on, or very strong bleach solution. The other members have posted some good ideas as well!
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post #7 of 15 (permalink) Old 02-02-2015, 01:43 PM Thread Starter
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Quote:
Originally Posted by Diana View Post
Simplest: Many diseases will die out without a host. If the Betta is OK where he is, just run the 10 with NO fish for a few weeks or so. Keep the beneficial bacteria alive with ammonia or fish food.

A little more complex: If you can treat the tank just like there is a sick fish in there, perhaps with antibiotics then this MIGHT kill off whatever killed the fish. But you do not know. Without a fish in there to show you by recovering, you do not know if you have chosen the right medicine.
You could try something pretty broad based and mild like Melafix and Pimafix. Make sure these are out of the water before you put the Betta back. These are not good for fish with labyrinth organs.

Most severe: Tear apart everything, throw away anything that cannot be treated and treat everything else according to what it can handle. If you try multiple treatments make sure you thoroughly rinse everything between treatments. Some of these could be tried without tearing everything apart. Assume these will kill the biofilter, and re-cycle the tank:
1 part bleach: 20 parts water for a few seconds to a minute (plants might survive, but so might disease organisms)
Stronger bleach: Will kill plants.
H2O2: Research the optimum strength. (See a thread in the algae forum called One-Two Punch)
Excel: See H2O2. Do the 1-2 punch.
Potassium permanganate: Follow all label directions.
Other: There are probably more ways to deal with this, but without knowing what it really is any treatment is just a shot in the dark.

Do whatever treatment you want, then buy some Harleys from a trusted source and add them before adding the Betta back, as guinea pigs.
Thanks for the write up. I may just trying keeping the tank empty for a while. There will still be a snail in the tank so I don't want to try anything too extreme.

FWIW, my tank water tested fine before adding these new fish.
0 ammonia
0 nitrites
40 nitrates

After fish started dying I started noticing some small jumps in ammonia (I assume this is from the dead fish sitting in the tank?). The worst parameters I witnessed during this time.

.25 ammonia
0 nitrites
60-80 nitrates (this was shortly after dosing fertilizer.

As of today the nitrates are back at 40 and there's a hint of ammonia still (between the first and second color on the API liquid kit).
post #8 of 15 (permalink) Old 02-02-2015, 01:47 PM
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40 is as high as like to let my nitrAtes go even in my overstocked tanks.
With 40ppm you still should do a 50% wc IMO(would get you to around 20).
The nitrates may have caused stress for the Harleys.
The ammonia would seem a clear indicator the filter(more over the BB) were not up to the load and also would be a source of stress IMO.

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post #9 of 15 (permalink) Old 02-02-2015, 02:22 PM Thread Starter
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Quote:
Originally Posted by Coralbandit View Post
40 is as high as like to let my nitrAtes go even in my overstocked tanks.
With 40ppm you still should do a 50% wc IMO(would get you to around 20).
The nitrates may have caused stress for the Harleys.
The ammonia would seem a clear indicator the filter(more over the BB) were not up to the load and also would be a source of stress IMO.
Yeah, I did two water changes yesterday to get the nitrates down to 40, I'll do another 50% change today. I'm dosing with osmocote capsules deep in the substrate, and seachem flourish....I also does seachem excel for carbon.

What are the chances that the rasboras are just that sensitive that a slight change in ammonia and nitrates would cause them to die off?
post #10 of 15 (permalink) Old 02-02-2015, 02:31 PM
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Yeah, I did two water changes yesterday to get the nitrates down to 40,

What are the chances that the rasboras are just that sensitive that a slight change in ammonia and nitrates would cause them to die off?
Depending on how much water you changed each time you nitrates could have been high enough to shock the Harleys.
If you changed 50% x2 and ended up with 40ppm then you were in the 150-200+ range.
Although a fish maintained in this environment may do well(although I will guess this is the real cause of betta issues)a new introduction will not have the same time to acclimate .

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post #11 of 15 (permalink) Old 02-02-2015, 05:38 PM Thread Starter
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Originally Posted by Coralbandit View Post
Depending on how much water you changed each time you nitrates could have been high enough to shock the Harleys.
If you changed 50% x2 and ended up with 40ppm then you were in the 150-200+ range.
Although a fish maintained in this environment may do well(although I will guess this is the real cause of betta issues)a new introduction will not have the same time to acclimate .
Well, I did a 50% Saturday, and then 20% x2 yesterday (highest nitrate reading I got was 60-80). Nitrates were at 20 today, ammonia is still giving off a slight reading (between the first two colors on the api liquid test).

I've had a heck of a time with this tank between being a total beginner and listening to the pet store to dealing with algae and slow/no plant growth, and now battling whatever is going on now.

My goal after this (if my betta makes it ok) is to work on figuring out why I stopped getting plant growth.
post #12 of 15 (permalink) Old 02-03-2015, 01:00 AM
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Never believe pet store people. The only word they really understand is, "Yes".
As long as you keep buying anything, it is OK by them.
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post #13 of 15 (permalink) Old 02-03-2015, 02:43 AM Thread Starter
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Never believe pet store people. The only word they really understand is, "Yes".
As long as you keep buying anything, it is OK by them.
Yeah, I learned that quickly with the retail/big box pet store employees fairly quick. Found a local mom/pop type fish place in town thinking they would be more knowledgable and helpful, that doesn't seem to be the case.

When I first went in there I asked what would be good to put in a little 10 gallon with a single betta in it, the gentlemen was knew enough to recommend some more gentle types of fish that wouldn't nip at the betta.

My wife decided she really liked the rasboras we chose, so I asked the guy how big they got, and if they would be able to be kept in a smaller group (3-5)...he of course said it didn't matter how many we kept and they won't get much bigger than an inch large so they would be ok with our little tank.

From now on we're going to go look for what we like, then come home and do our own research instead of bothering with fish store employees.

On a separate note, the 5th (final) rasbora is showing signs of dying now, swam upside down for a minute not too long ago, also swimming at the very surface of the tank.

ammonia is still present (between this first and second color)
nitrites are still 0
nitrates are going back up?? was ~40-60 before I changed the water again today.
post #14 of 15 (permalink) Old 02-03-2015, 05:00 AM Thread Starter
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And the 5th rasbora just passed. So, every single rasbora I put in the tank died in 5 days.
post #15 of 15 (permalink) Old 02-03-2015, 02:25 PM Thread Starter
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With the 5th and final fish in the tank dead, I'd like to concentrate on getting my plants growing healthily. I feel like the plants aren't doing well if I'm getting ammonia and nitrates in my readings.

I dosed with osmocote plus diy tabs (4 tabs, too much??) about a week ago. I dose with Seachem Flourish about once a week, and Flourish Excel roughly every day.
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