Sick Koi

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captainmoss

Aquarium Advice Apprentice
Joined
Feb 20, 2015
Messages
12
Hi - I am new to this site - but I am hoping that someone can help me.
We have two large (12") koi and several smaller koi/goldfish. From April to November, the large koi and some of the mid sized ones go in our pond outside, while the smaller fish stay in our 55 gallon aquarium.
In the winter months, we bring all the fish inside. This has been working perfectly for about 7 years.

On January 2'15, we set up a new 70 gallon aquarium and transferred the fish. The old tank went to my work office along with some of the small fish.
By about Feb 5'15, the fish in the 70 gallon aquarium started acting weird - staying on the bottom, swimming erratically (diving to the bottom and then basically doing somersaults), open and closing their mouth quickly, etc. I understand that this is the result of stress. I tested the water and I don't see any problems. PH is 7.5, Ammonia is 0.5. We do have hard water, but I don't think that is a problem for koi or goldfish - and our water has always been hard - so it is nothing new.

It was getting so bad that we assumed it was something to do with the new tank and we put the fish in a large Rubbermaid bin in the basement. They seemed fine there. We replaced all the water in the 70 gallon tank and put the fish back a few days later. After a few hours, they started going crazy again. One of the big koi even looks like he is bleeding internally - you can see orange or red through his skin and in his fins.

I don't know what else to do. Please help. The large koi have been in our family for over 10 years and we don't want to lose them.
 
I have a liquid solution tester for Ammonia and test strips for Nitrite / Nitrate. All results are coming up at 0 - so shouldn't that mean that my water is cycled?
 
You said you were reading .5 ammonia in the 70? It sure sounds like ammonia problems to me. If you are not reading consistently 0 in ammonia and nitrite it will cause problem. And the fact that you see 0 nitrate could mean your 70 is still cycling.

You said they did fine in the tub though. Was that tub filtered and how big was it. Maybe you have build up of waste in the substrate of the 70 gallon that is breaking down into ammonia and proving too much for your filters?
 
The tub has a small filter on it that was used on a previous tank. The koi are still in the tub and they seem fine - they don't swim much, but they are eating and are not acting stressed. I would guess that the tub is about 30 gallons.
The 70 gallon tank is now testing at 0 for ammonia and nitrate/nitrite (does that mean it is cycled?). I tried moving the large goldfish back into the big tank and he does not seem happy there, he won't eat or move - even though he was fine in the tub. But maybe he is just getting used to the new water.
Do you think I should move the koi back now?
 
The tub has a small filter on it that was used on a previous tank. The koi are still in the tub and they seem fine - they don't swim much, but they are eating and are not acting stressed. I would guess that the tub is about 30 gallons.
The 70 gallon tank is now testing at 0 for ammonia and nitrate/nitrite (does that mean it is cycled?). I tried moving the large goldfish back into the big tank and he does not seem happy there, he won't eat or move - even though he was fine in the tub. But maybe he is just getting used to the new water.
Do you think I should move the koi back now?

that big of fish can only stay in a 30 gallon so long before you'll have ammonia problems in there too.

The only way to know for sure that the tank is cycled is to see 0 ammonia and some positive number for nitrates. If you saw .5 ammonia once and 0 nitrates than it is still cycling.

Is ammonia/nitrite/nitrate 0 in the tub too? Perhaps when you move them over to the 70 you should move that filter over too to get them through a possible cycle.

If they are acting uncomfortable even with ammonia and nitrite at 0 perhaps they are not used to the lights on the 70?
 
also the test strips are notoriously unreliable. Perhaps you have nitrites that you can't see on the strips?

If it were my fish I would do a 100% change on the empty tank and treat with prime. Any nitrItes I couldn't see would be gone. Then a 50% change on the tub (so if there's any change in conditions between the tub and the tank it will be minimized.) Then I'd acclimate them back in the 70 G tank with the lights off with both the new and old filter running. Then test test test to be sure you are not cycling. (Ideally I'd go get a liquid nitrIte test kit too)
 
What do you have for a filter on the tank (be specific)?
You might need to have the 55 back home to handle that much fish (like the monster koi in the 70 and the rest in the 55.
You want plenty of filtration power. Do you have a heater? I think most people don't use heaters for koi ???


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I have an AquaClear 110 filter system - this is the first time that I have used a biological filtering system. My other tank uses the replaceable cartridges. I do have a heater, but I have taken it out - thinking it might be the problem - but you're right I didn't really ever need one for koi.
I will go to the store tonight - do you recommend using this 'Prime' - will that allow me to go ahead and put the Koi back in?
 
... uncycled, with a tonne of koi... ammonia is going to be insane and deadly

just a thought... why did you ever take them out of the pond.
yeah it freezes over, but thats why you get a pond heater and bubbler, it keeps and opening for gas exchange and keeps the water at the bottom a decent temperature for the fish. they sleep most of winter from what i know...
 
What do you have for a filter on the tank (be specific)?
You might need to have the 55 back home to handle that much fish (like the monster koi in the 70 and the rest in the 55.

I was under the impression that's what captainmoss was doing. Either way ammonia will climb in that 30 gallon tub with such large fish in it, so they need to get back in the big tank with lots of filtration asap.

The 110 is a decent filter but if it's a new filter it will take some time to cycle. At a minimum you should be running the cycled filter from the 30 gallon tub alongside the relatively new 110.

I will go to the store tonight - do you recommend using this 'Prime' - will that allow me to go ahead and put the Koi back in?

If you're cycling, prime will help detoxify the ammonia/nitrites but you'll still have to test a lot and do water changes.

Like I said I don't think conditions will be good in that tub for very long so yes, I would get them back into the 70.

just a thought... why did you ever take them out of the pond.
yeah it freezes over, but thats why you get a pond heater and bubbler, it keeps and opening for gas exchange and keeps the water at the bottom a decent temperature for the fish. they sleep most of winter from what i know...

Sounds reasonable but I'm no koi expert. Depends on where it's located probably whether they can overwinter safely.
 
What is the best sign to show that the tank is done cycling? My ammonia/nitrite and nitrate are all 0. Yet, when I put one of the goldfish back into this tank, he went crazy - after 24 hours, he was almost dead - lying on the bottom and occasionally falling to the side - and his color turned from pure white to almost orange. I took him back out and put him in the tub and he has recovered somewhat - but I think he sustained permanent damage - his eyes are all cloudy - I don't even think he can see anymore.

Could there be something else going on here - I am almost ready to give up - it is very stressful. How could a tank that has 0 reading on all the key indicators be so lethal to a fish in only 24 hours. Could the biological material itself be giving off toxic chemicals?

My water is very hard - but I believe that both koi and goldfish like that. And my pH is 7.5 - which I understand is acceptable as well. So - I can't see what is wrong with my tank.
 
This does seem strange. So just to be sure we understand this the fish are fine in the 55 gallon and the tub and only do poorly in the 70 gallon?
The color change and eye cloudiness are probably due to mucus production in response to the funky tank.
Did you use any sort of cleaner on the tank? Alternatively maybe some cleaner was used on it before you got it?
The fish should be fine in the 55 and tub until you figure it out. Just do 20% water changes every day on the tub especially conditioning the water with Prime. Monitor the ammonia and change more if necessary.
Then start over with the 70. Empty everything. Don't use any cleaners or chemicals. Just flush everything with tons of tap water. Put it back together fill with conditioned water. Put a "dirty" filter pad from your good tank underneath the sponge in your Aqua clear. Follow the instructions for fish less cycling. It takes about 2 weeks. First you see nitrites showing up. When the nitrites drop down put a fish in.


Sent from my iPhone using Aquarium Advice
 
This does seem strange. So just to be sure we understand this the fish are fine in the 55 gallon and the tub and only do poorly in the 70 gallon?
The color change and eye cloudiness are probably due to mucus production in response to the funky tank.
Did you use any sort of cleaner on the tank? Alternatively maybe some cleaner was used on it before you got it?
The fish should be fine in the 55 and tub until you figure it out. Just do 20% water changes every day on the tub especially conditioning the water with Prime. Monitor the ammonia and change more if necessary.
Then start over with the 70. Empty everything. Don't use any cleaners or chemicals. Just flush everything with tons of tap water. Put it back together fill with conditioned water. Put a "dirty" filter pad from your good tank underneath the sponge in your Aqua clear. Follow the instructions for fish less cycling. It takes about 2 weeks. First you see nitrites showing up. When the nitrites drop down put a fish in.


Sent from my iPhone using Aquarium Advice

That's bizarre. Clearly something is in there that is not your standard nitrogen cycle products. I think maybe Dotrskeeper has hit it on the head... some kind of cleaner?

Was the tank new when you got it? I assumed it was but if not maybe a previous owner did something weird to it? Are you running carbon in the 70? to pull out any miscellaneous chemicals that might have somehow gotten in the tank.
 
It was a brand new tank from Petsmart - but I get the feeling it had been in their store for quite a while. But remember, I had all the fish in the tank from the start of January to the start of February with no problems - and then things started to go bad. If there was a chemical in the tank wouldn't the fish have acted sick right away?
 
It was a brand new tank from Petsmart - but I get the feeling it had been in their store for quite a while. But remember, I had all the fish in the tank from the start of January to the start of February with no problems - and then things started to go bad. If there was a chemical in the tank wouldn't the fish have acted sick right away?

well that puts a damper on that theory...Regardless are you running fresh carbon? Any kind of contaminant/heavy metal build up etc will be helped by running carbon for a while.

I assume you've done full water changes with gravel vac already in case their was some kind of gas pocket under the gravel or something
 
Out of interest and a long shot, but is the ph and temp the same in all the tanks and Rubbermaid container? You would have more toxic ammonia in your total ammonia/ammonium test result at higher ph or temp.
 
Out of interest and a long shot, but is the ph and temp the same in all the tanks and Rubbermaid container? You would have more toxic ammonia in your total ammonia/ammonium test result at higher ph or temp.

Interesting thought but the liquid test for ammonia said 0...
 
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