Something Is Wrong With My Koi, Please Help!

[abyss56]

Size of aquarium/pond - 55gal

Types of fish - koi

Number of fish and sizes - five 5-8 inch

Filtration used and how do you clean it and how often - aqueon 55/75 and aquaclear's 55+ gallon filter (not sure model #), cleaned once a week

How much in the way of water changes and how often -- 25-50% every 3 days

Do you dechlorinate - yes,tetra aquasafe+

Symptoms of sick fish ie, spots, behaviour, etc - solid black koi has what look like white scratches all along his left side. Started as what looked like a missing scale, but has the appearance of scratches now. Other koi have the occasional odd looking scale, but nothing like this. I can't take a picture less than 300kb...

How long has the fish been sick and which medications are your currently using or recently used - fish acquired recently (a week ago) so not sure of sickness duration. "Scratches" have worsened in appearance every day since I noticed them (about 4 days ago). Currently trying to add salt to tank, raise water temp above 78, and using kordon anti-ich treatment

Test results for ammonia, nitrite, nitrate and ph both from the tap and tank - all good from tap. Tank: api test for ammonia always reads 8ppm/dark green (no idea why?), even after 50% water change. All others are within spec. Seachem ph gauge stuck at 8, api says 7.3 - seachem ammonia guage says .05, is api test unreliable?

Anything else you need us to know - nothing in tank for koi to scratch themselves on. No gravel or substrate. I also have a powerhead 70 running in there 24/7.

 

[sawickib]

Koi are NOT meant for home aquaiums, esp a 55 gallon, i suggest you rehome them.
.5 ammonia is very bad, id do a large water change.
Not sure about the scratches though sorry.

 

[attibones]

Test results for ammonia, nitrite, nitrate and ph both from the tap and tank - all good from tap. Tank: api test for ammonia always reads 8ppm/dark green (no idea why?), even after 50% water change. All others are within spec. Seachem ph gauge stuck at 8, api says 7.3 - seachem ammonia guage says .05, is api test unreliable?

Anything else you need us to know - nothing in tank for koi to scratch themselves on. No gravel or substrate. I also have a powerhead 70 running in there 24/7.

API liquid tests are quite reliable, especially their ammonia and nitrite tests, though they are fallible tests. However, with your tank stocking, I'd say it's pretty accurate. You should be doing approximately 100% water changes daily with five of these species of carp. Definitely rehome them. I'm guessing the fish's wounds are from poor water quality. Did you ever cycle this tank? If you are unfamiliar with this process, check the last two links in my sig. They'll help you out. 
 
In the meantime, daily water changes, high volume, water change every time you get an ammonia reading. Those gauges you are talking about are probably not the most reliable. I've heard mixed results about them, so I've never purchased any of them. The issue, I hear, is that they take a long time to adjust to new parameters. 

 

[abyss56]

I should have specified that the koi are indoors because we've had negative temps outside and I can't keep the pond from freezing. I have a 6000gal outdoor water feature that my koi stay in when it's above 50*F.

I have them in the 55gal as a hospital tank. When I bring them inside, normally they are in onw of my 150 gallon tanks. But as soon as I noticed this issue, I relocated any affected fishies to the smallest unused tank that I had available. I have 2 150's and 2 55's, of which only one 55 was unused.

I have cycled all of the tanks, though admittedly I had to improvise the setup for this tank on the fly. I have fx6's running both 150gal tanks, and 2 HOBs on each 55. I do not overfeed, and my filters have kept up with more heavily stocked tanks than this (for brief periods of time).

I'm really not sure what's causing the problem with the ammonia testing. I was thinking it might be my "overuse of additives" (as my friend calls it).

 

[attibones]

Had the filter been in a tank with fish before you put in this tank? If not, you could have lost all your ammonia. My advice is still to do a total water change, test your tank with the liquid tests after that 100% water change and see what the results are. That should knock out the crazy ammonia reading. If it doesn't, then your tests are faulty.

If you can upload a picture to photobucket or some other similar site and put the link here, we may be able to get a better diagnosis. For now, start with clean water.

How deep has the pond been freezing? Many times goldfish and koi (perhaps not the very fancy varieties) live perfectly easily under the ice.
What additives have you been using, by the way?

 

[MBOU]

I honestly would suggest getting plastic vats to go in a shed or garage and pond filters if you know you are going to be bringing the fish inside each year!! Can be purchased fairly cheaply...
 
I wouldn't be surprised if your ammonia is that high, I also advise doing 100% water change and do at least 50% changes a day or every other day. I would also be chucking a bacteria supplement at the tank to help it cycle as fast as possible. Poor water quality is likely the cause of the infection or at least exacerbating it and so treating the water is more important than treating the fish. Medications strip oxygen from the water as does ammonia and those fish desperately need high levels of oxygen. 

 

[tunagirll]

This may be a dumb question but is it feasible to add a heater/deicer to a pond? I only ask because I know horse people will toss them into water tubs to stop them freezing over.

 

[livelifelow]

It is, my family actually used a horse trough heater in our pond this year.