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FAQs About Koi Kept in Aquariums

Related Articles: GoldfishGoldfish Varieties Goldfish Systems, Goldfish Disease

Related FAQs:  Goldfish 1, Goldfish Behavior, Goldfish Compatibility, Goldfish Selection, Goldfish Systems, Goldfish Feeding, Goldfish DiseaseGoldfish Breeding/Reproduction

Scaredy cat Koi      7/15/15
Dear Crew.
I have two Koi in an indoor 55 gallon tank,
<Will need, or may require more room right now>

they have been in this tank for almost two years now and they are doing great and thriving and growing. But they still scatter and panic when someone walks into the kitchen where the tank is kept, hitting the rocks and glass walls of the tank beating their beautiful heads off, but no injuries yet ; )
<Uh, yes there are>

Any advise would be grateful...
Thank you!
Mr. John C. Hanna
<A much larger system or a move to a sizable pond.
Bob Fenner>
RE: Scaredy cat Koi      7/15/15

Well thank you for not answering my question! I live on a river and have a Great Blue Hereon problem they ate all the Shubunkin fish but left the Koi
<Ah yes; Herons can be very hard to guard against>
so I brought them in I love my fish and was devastated at the loss and did not want to leave the others to the same fate...
<Mmm, perhaps reading on WWM ahead of writing; as we direct folks... There are anti-depredation techniques to consider>
You know you all had several rules on sending in an e-mail I know that there are people out there that do that kind of stuff,
I do not feel that the "between the lines comments" are necessary. And if I where your Supervisor you would be fired!
<We have no supervisors, and are all volunteers. Perhaps my pond books (see Amazon) are more your speed>
Once again thank you for your courteous answer.
John C. Hanna
Customer Service Supervisor
Mr. Suds Inc.
<Read John; don't hate. BobF>

Hi; Nishikigoi in sm. aq.s    9/1/13
I just bought an  Aqueon 15 column aquarium and have 5 small koi's in there and I don't know nothing about fish plz help.
<Umm, really? Is this system cycled? Koi can't live in such a volume...
Please read here:  http://www.wetwebmedia.com/FWSubWebIndex/koiaqfs.htm
Bob Fenner>

hi (Koi and Iridescent Sharks in 55 gallons… can I add an Oscar?)   Wacky FW mixes  6/16/13
hi, First of all let me tell you that you are running a great site. Lots of useful information. Thanks a lot .
<And thank you for the kind words.>
Now about my issue. I already have a 55 gallon tank.
<A great size for an aquarium!>
I have a 5 inch & 2.5 inch Koi,
<Whoa! Not in this tank for long
… Do bear in mind that a healthy Koi will get to around 2 ft/60 cm, and they're sociable animals too, so keeping in an aquarium isn't really viable.>
two 3.5 iridescent sharks
<Same again! These get massive,
potentially over 2 ft/60 cm even under aquarium conditions, and something like twice that size in the wild. Most aquarium specimens die long, LONG before that because they can't be kept properly in home aquaria.>
& one 5 inch Pleco.
<Do-able, but will make the tank filthy; would always favour a smaller Loricariid catfish in 55 gallon and smaller tanks, e.g., an Ancistrus or for the more ambitious, something like the Green Phantom (Baryancistrus demantoides) which gets to around 15-20 cm/6-8 inches.>
Is my tank already overcrowded???
<Oh yes.>
I want to add two 2 inch albino red Oscar. Is it a wrong move?      6/16/13

Oscar will be too aggressive to other tank mates???
<Not as such, no. Oscars are not aggressive fish outside of spawning, and actually work well with large barbs (e.g., Tinfoils and Spanners) and L-number catfish. But a single Oscar will fully occupy a 55-gallon system in terms of filtration, water quality and water changes -- even adding a catfish will make it VERY HARD for you to keep the water quality right, especially in terms of nitrate.>
If Oscar is not a good choice then can you give me few good choices???
<I would start over with this aquarium entirely. Have a look at a peaceful, medium-sized cichlid like the Blue Acara or Firemouth if you want a mixed species set up, then choose companion species of appropriate size to go along with it. Firemouths for example work well with Swordtails, while Blue Acara could be kept with medium-sized tetras such as Bleeding Hearts or even Rainbowfish if you don't mind a "non South American" mixture. Both would get along well with L-number catfishes in the 10-20 cm size range. If you just want cichlids, then Tanganyikans are especially nice cichlids to keep, with numerous Lamprologus and Julidochromis species being just the right size to fit into a tank like this.>
My Other issue: I'm planning to buy a 22-24 gallon tank. This one will be a planted aquarium. I'm planning to add neon tetras. How many tetras will be enough in this tank???
<Neons do best in large groups, and this tank is easily big enough for 12-14, and that would still leave space for one or two other small species, perhaps 3-4 Corydoras and a single specimen fish like a Dwarf Gourami.>
I'm thinking about adding full red guppies & full black guppies. Is it a good move?
<With Neons? It's doable, but Neons do need fairly cool (22-24 C/72-75 F is ideal) water that's soft and acidic (certainly no harder than 15 degrees dH). Kept otherwise they are alarmingly difficult to keep alive for more than a few months, especially the cheap, disease-prone farmed ones sold in most pet stores. Guppies are equally disease-prone and farming has done them no favours at all, so again, you're fighting with one hand behind your back if you try to keep them in less than perfect conditions. If this was me, and I wanted to keep Neons, I'd tailor the tank around their needs as described above, and if Guppies, I'd want a hard, alkaline system with the definite option of adding a little salt, which rules Neons right out. Thirty years ago both Neons and Guppies were quite hardy fish, but that isn't true any more, so I'd treat both species as "demanding" fish that need a little molly-coddling.>
What's your suggestions for a 24 gallon tank???. Please suggest fishes which don't try to uproot my plants.
<Assuming your water is neither too hard nor too soft, so around 5-15 degrees dH, pH 6.5-7.5, then my favourite hardy and commonly sold fish for planted communities include Cherry Barbs, Dwarf Rainbowfish, X-Ray Tetras, "False" Penguin Tetras, Emperor Tetras, Bronze and Peppered Corydoras, Bristlenose Plecs and Whiptail Catfish. None of these will be hard to keep and all thrive across a broad range of water chemistry and temperature values. Danios can also be excellent, but in small groups (6 or fewer) they sometimes become aggressive, so approach with caution. Of the commonly sold livebearers, Platies are about the least troublesome, but remember they must have hard water to do well and will be sickly if the pH is below 7. Swordtails and Mollies need more space than you can provide, and are demanding in other ways too. If this was my tank, I'd probably go with Cherry Barbs for midwater colour and activity, a school of Corydoras for the bottom of the tank, and maybe Leopard Danios for the top of the tank.>
Thanks a lot for reading my mail. Please reply. bye
<Most welcome, Neale.>

Koi carp, infected scales?    12/28/12
Hello crew,
I needed your help regarding the condition of my carp. As you can see in the picture the scales are popping out and they are bleeding probably.
<Perhaps Carp Viremia; though bacteria, simple mechanical injury might account for this appearance, the one only being affected>
The other carp is fine. The affected carp is also showing normal behaviour but since there are no improvements, so I thought it would be better to consult
you. The capacity of the tank is 180 litres, temperature is around 25 degree Celsius, and other inhabitants excluding the carps are two turtles.
<Poor tankmates... see WWM re... the search tool on every page>

This happened a few weeks ago and I do not know what should be done.
Thanking You
Nalin Khurb
<Improved water quality (removal of turtles esp.), and nutrition (I suggest Spectrum pelleted...) are the only (indirect) methods of "treatment" of use here. No direct. Bob Fenner>

Questions on how to properly house Koi fry until my pond is built    8/4/12
Hello folks,
I have recently moved from Virginia to Florida, and had acquired 14 Koi fry right before my move.
<Fry? How small>
They made the 14 hour trip in the moving van just fine (I was scared to transport them, but stuck an air stone in the bag that was on the whole trip and they made it!). I have since put them into a 10 gallon aquarium until I get my pond designed and built here at the new house. I have not had good luck lately, in the past week 2 of my babies have died, oddly enough they were 2 that I considered to be the strongest and fastest growing of the bunch. All are under ¾" long. I have one that is stunted - the same size as when I got him in the middle of June. There is also 1 small Cory cat in the tank to help with cleanup. =)
<Should be fine... do know BTW, that fishes period, cooler water species more so, often have a lag time in showing stress... dying days after an insult/challenge>
I have had problems with the tank being cloudy, even while doing daily 40% water changes. The nitrites and ammonia were pretty bad for about a week, but are now finally getting under control. Here are the readings currently:
Nitrate - 0
Nitrite - .5
<Needs to be 0.0>
Hardness is at 0 - we have a water softener system on the house... I don't know how to fix this (?)
Alkalinity - 300
PH - 3.4
<No... please check again... needs to be neutral to slightly alkaline... 7-8 or so>
My questions are:
Should I get a preformed "water garden" container for them instead of the tank?
<A ten gallon should be fine for a couple, three months... w/ moderate feeding, regular (small percentage... 10-20%) water changes>
The filter just doesn't seem to be cutting it to me. On that note, how can I find a filter for one of these container gardens that will not suck my babies up?
<Look into a sponge type>
If they are in a larger container garden, do they actually need a filter, or just plants and air?
<Koi need a 24/7 filter, water movement>
The guy I got them from did NOT have a filter in place.
Should I keep them where they are, and if so, can you suggest ways to fix the problems with my water? Maybe upgrading to a much better filter?
<Yes to the better filter, an additional one>
I am feeding them twice daily (they are little piggies usually - but not so much as when I first got them) Omega One Natural Protein Formula Super Color Flakes for tropical fish
<Need lower protein... less than 20%... pellets are better than flakes>
as I cannot find a food specifically for Koi that is small enough for them to eat. I crush the flakes before feeding. Any suggestions here would be greatly appreciated.
The last baby that died had blood in his eyes...
<Likely the ammonia and/or nitrite>
yesterday he swam listlessly for about 30 seconds and then was fine. I thought maybe he hit his head on the tank. One other baby had done this a few days ago, but he is fine. He did not have the blood in his eyes while he was alive.
Thanks so much in advance for your comments/suggestions!
<Welcome. Bob Fenner>
Re: Questions on how to properly house Koi fry until my pond is built     8/14/12

Hi Bob  =)
Last I wrote I was having issues with pretty much everything.  I am happy to report no more casualties, both nitrates and nitrites are at 0, Hardness is now "hard" instead of soft, PH is 8.4.  I have changed their food to a floating stick that softens... they love it.  It had the lowest protein formula I could find, at 28%.
I've upgraded the filter - and the water is spectacular.  I bought a plant for the piggies to munch on.
Now one of the babies has what appears to be ick on his tail.
<Don't panic! And don't treat... if one "dot", not Ich, nor likely parasitic... most likely just a physical "bump">
 I'm not quite sure he could get this from a plant, but I have no other idea where it could've came from.
Should I pull him out?
 Should I treat the whole tank (and if so, any suggestions would be much appreciated.)?
Thank you in advance for all of your wonderful help!  You guys are true lifesavers!
<Welcome. BobF>
(PS - you will get a bounce back email that I don't exist... I assure you I do.  =)  )
Re: Questions on how to properly house Koi fry until my pond is built     8/14/12

Hi Bob,
Wow that was a quick response!  I just wanted to make sure - don't add any salt or anything to the aquarium?
 After staring at my little guys tail for awhile - it appears to have a moldy type look to it... its probably the size of a pin head - but the fish isn’t that big  ;)  It looks raised when looking at him from an angle.
I just don't want my babies to die. 
Thank you for all your help!

Koi with bulging eyes and bent tail    6/18/12
PLEASE HELP. I have had my Koi Sol for about 5 years with 2 other Koi that have never been sick.  About a year ago Sol developed some sores that after treated with antibiotic food would usually go away, but then they kept coming back in different places.
<Mmm, the pandemic, Ana aki, Furunculosis... see WWM re>
 They were in a 10 gallon
<Way too small a volume>
 till the sores appeared so i moved them about 6 months ago to a 30 gallon and a new filter which doesn't seem to work.

 Sol has gotten sores ever since the move.  Sols eyes started bulging probably a year ago nothing i do gets them down, after the antibiotic treatments for the sores the eye swelling goes down but never goes away.  I recently added zeolite to the filter because i couldn't control the ammonia
<... toxic>

and was told that was why he was getting the sores.  Now about a week ago his tail started floating up, and each day it got worse.  Yesterday he was upside down, so I treated with QuickCure and salt which worked years back when he had swim bladder issues.
<All these issues are environmental in origin/cause... Fix the env.>

 Now he's right side up but has trouble swimming and his tail keeps moving up, it looks like something is pulling him up from the tail and it starts bending at the anal fin.  I have had so much trouble trying to find out what is wrong, everyone tells me check the water, but the water seems okay and the other two fish have never been bothered AT ALL.  Sol started laying at the bottom a couple of weeks ago but every time I came in the room he would swim up and get excited, and whenever he knew i was there he would swim around. 
During all of this he has still eaten and swam normally until yesterday, what else would cause the tail to bend up and cause him to float like this.
 He has been dealing with these problems for a while now and has not shown any signs of lethargy or as if anything were wrong until recently.  Sol has a very strong will to live and he is very happy and excited to see me even though he can hardly swim.  I need to know what i can do to help him get better because i know he will if i just knew what was wrong. thank you.
<All these issues are environmental in origin/cause... Fix the env.>

<... read here: http://www.wetwebmedia.com/FWSubWebIndex/koiaqfs.htm
Bob Fenner>
Re: Koi with bulging eyes and bent tail  6/19/12

is zeolite harmful to Koi?
 There are no nitrites and nitrates and almost no ammonia.
<Any ammonia is... have you read where you were referred?>
  You're telling me that he has been having sores and bulging eyes for a year because of the environment while the other two have never EVER had anything wrong.  How do I fix the environment and why is his tail bending?
<More, better filtration>
 He also gets what look like blisters under the skin.  I cannot put them in a larger tank it is impossible to do appropriate weekly water changes in anything larger.  If doing weekly water changes and keeping the ammonia down were the problem he would not be sick from these things.  How can he be sick off and on for a year and not get better if it was ammonia.  Please Help.  There is gravel at the bottom what is a better alternative?
<... Please read, don't write till you have. B>

Bully Koi    5/24/12
I really need help with this one. I have two very small Koi, a butterfly Koi and a regular Koi. They're both only about 2 inches long, and for now i have them in a 10 gallon tank. I know its fairly small for these kind of fish, but it has to do for now until I can clear the room to get a larger tank in here. Anyways, when i introduced the butterfly Koi, they got along perfectly fine for a few days. But lately, the original one in the tank has been pushing and bumping into the butterfly. The butterfly doesn't do much about it, just swims away after a few bumps, but sometimes the other Koi will chase the poor thing around the tank. Also, I believe there was an ammonia problem in the tank as well.
<Trouble... and likely related to the misbehavior. There must be 0.0 ammonia...>

I did a test and have been treating the water with ammonia eliminator since.
<Of no real use... need sufficient bio-filtration>
The fish are no longer showing signs of sickness, but the original tank dweller is still bullying the butterfly Koi. I've tried separating them a few days and reintroducing after moving the objects in the tank around. It seemed to work for about a day, but then the bullying continued. The fish are pretty much the same in size, and the bullying hasn't left any damage to fins or scales. The only difference in size is that the butterfly is slightly more slender and the other one is more bass-shaped. Any advice will be greatly appreciated! Do you believe its an issue with space, or territories? I'm hoping its something more innocent.
<... water quality mostly. Bob Fenner>

Koi with red lump/sore on side of tummy   1/23/12
Hi I have an at least 4 year old Koi about 4 inches long
<Badly stunted>
 in a 10 gallon tank with 2 other small Koi,

<Need much more room than this>
they have lived together for years and i had one more until about 4 months ago, when he suddenly died.  My problem now is that i recently moved them about 4 months ago after the Koi died and cleaned the tank and rocks and filter, then a few weeks ago i noticed a terrible film on the top of the water, so I cleaned the filter and there was thick greenish brown muck clogging everything and little black things.  Then i replaced the carbon and filter pads, and the film was still there.  I thought maybe they had spawned because the small one kept brushing on the larger ones, but they are only 4 inches long tops.  So the other day I noticed a lump on my koi's side, which only looked like a small bump with no discoloration or redness, so i watched it and the next day it was larger and red.  As the day progressed it got even larger and very red and bloody with a small vein next to it.  I looked everywhere for solutions, so i treated them with tetracycline for 4 days
<Of no use>
 and did the recommended water changes, and siphoned the gravel.  During the treatment the redness went away but the lump was still there, and the day after the treatment was done the redness immediately came back like i didn't treat it at all.  I need to know what parasite to treat for, or what is going on, there seems to be no answer for this anywhere.  It looks like a giant pimple on his side, with a white thing in the middle, and a large lump underneath, it is the only one so far and no one is acting different, they want more food as usual. Please help this is my oldest Koi, and I love them very much.
<Please read here: http://www.wetwebmedia.com/FWSubWebIndex/koiaqfs.htm
The only way to improve and lengthen the lives of these fish is to get them into a bigger and better environment. Bob Fenner>

Koi tank  12/14/11
I have a 10 gallon Koi tank.
<... there is no such thing... Akin to a closet dream home>

  Normally it has 2 small Koi in it 3-5 inches long.  Last year one of them died
 i don't remember the specifics cause sometimes they just die and the other remained healthy.
<Stop. Read here: http://www.wetwebmedia.com/FWSubWebIndex/koiaqfs.htm
Good bye Bob Fenner>
  This summer I bought another small Koi to put in with it.  The next day the new Koi started floating head down along the bottom of the tank. 
within 2 days it was dead.  The store replaced it and then the one which i had over a year started to do the same thing and died.  I went back to the store and the 2 suggestions that I received were that it might need more aeration the other was build up of nitrogen.  I thoroughly cleaned out the gravel and purchased an air pump besides the filter.  The remaining fish seemed ok although it never really was an active swimmer and remained at the bottom of the tank.  Now in December, yesterday i saw it doing the same
thing as the other two had.  It stops swimming along the bottom and the tail end just floats up like it is doing a headstand.  Is this a swim bladder disease problem or something else?  every site i go to talks about goldfish and not Koi.  And i haven't come across any that refer to floating at the bottom of a tank.

Koi help...     12/5/11
I am new to your site but not new to fish. I have grown up with all kinds but I've stumbled upon a problem that I just can't solve.  My fiancé and I have a 150 gallon indoor tank. We have 2 Koi, 2 Plecos, 2 Oscars (they don't mess with anything as everything else is bigger for now),  a parrot fish, and 2 map turtles.
<Mmm... too much and dissimilar environments needed here to keep all together... The Koi need cooler and larger waters, the Map Turtles are too  ]dirty... the cichlids and Pleco can live together>
Now my black Koi is the one with the problem the other orange and white is perfectly fine they are both roughly 8 to 10 inches in length. Lets start with a little back ground, we had a few more Koi awhile ago and we had a terrible ammonia spike that killed out biggest Koi friend and the butterfly Koi.
<See my notes above>
 The black one and orange were there then to but they survived. Everything has been taken care of and we monitor the levels very close now (which are all pristine). For some reason the black Koi still swims to eat and sometimes messes with the gravel like normal but it always returns to laying on the bottom.
<This type of Nishikigoi is close/r to the wild type (Chagoi)>
 It's kind of like it gives up after a few seconds if there is no food. It doesn't have any sort of labored breathing the only noticeable thing is it's missing a few scales because we used to have a gourami in the tank (who is now moved). Like I said earlier nothing messes with it and the orange one tries to make it swim by swimming around it, it only works sometimes. The black Koi was our second Koi ever and I don't know what to do.
<Plan, dig a pond...>
I'd hate to see it gone. The filtration is great and aeration too. It has been set up for almost a full year now but it's only been a couple of months since the ammonia incident. Any advise is greatly appreciated, we love to watch them and so does our Chihuahua.
Thank you for your time,
<Do consider what you're about here. What you have is an untenable mix of life crowded into too small a world... Bob Fenner>

Japanese Koi URGENT   3/12/11
Hi Crew,
Good Evening, Ethan Ong from Thailand. I raise Japanese Koi in a tank. Last Saturday, one of the Koi accidentally suck by my water pump on it lower stomach.
<Unusual... healthy Koi almost always avoid such>
It did survive and yesterday I saw the skin come out thinking that the new skin coming out. This afternoon I catch it to have a look. I can saw the flesh but no new skin. The fish is still active and eating food. Will the skin grow back? My fish is just 7-8 inch only.
<Hopefully so; and generally yes, if there is not "too much" damage... Do provide extra care in water quality and nutrition. Bob Fenner>
Re: Japanese Koi URGENT   3/13/11

Hi Bob Fenner.
I'm using Tetra Pond MediFin
The wound is as big as 1 inch. Very sad to see it. Will this products work for it?
Should I separate it? Do I need to remove the skin that still hang on the body?
<I would leave this fish in place (DO cover/screen that pump intake!) and leave the skin in place as well. BobF>
Re: Japanese Koi URGENT   2/13/11

Hi Bob Fenner,
Thanks. Your reply make my worry less, I care for every life of my fish.
God bless you.
<Welcome! B>

Koi Help (RMF, any tips on Koi indoors?) <<Not here, no. RMF>>   10/17/10
I have 3 Koi in a 75 gallon tank.
<There's your problem. Koi do extremely bad in aquaria, and 75 gallons really isn't viable. Even 200 gallons would be barely acceptable.>
Last year one of the fish developed Fin Rot and a Cotton Growth at the sides of its mouth. For the last year I have treated with Melafix and numerous treatments with Kanaplex. Seachem told me it would not overdose the other fish and should resolve the problem.
<Indeed, these medications should be safe, but because environmental conditions are wrong, medicating these fish will be a perpetual thing. It's like giving someone contaminated water to drink every day. Sure,
antibiotics would cure the disease of the week, but darn sure they'll be sick again before long.>
At one point the mouth seemed to clear up. My Koi has reached the point that most of the fin is missing on one side and the mouth area is getting worst.
So far, the fish is still active and eats. My tank is cleaned by a company every 3 weeks, at which time the water is always tested. I know the water conditions are good.
<Really isn't. Even if ammonia and nitrite levels are zero, which I doubt, nitrate levels will be high, and oxygen content will be low. Plus, between water changes there will be pH drops that are suddenly put right every three weeks.>
I love this fish and am in a real panic at this point for fear the rot will reach the body, plus the area around the mouth is sticking out more now.
Please help me in saving my fish.
<Alice, honestly, this isn't going to work; I don't know who told you Koi can be kept in 75 gallons, but they sold you a bill of goods there. Yes, Koi are amazing fish, and yes, they do become truly tame, even friendly, in a way few other fish do. But they are pond fish, and they have been bred for pond conditions across hundreds of years. Some of the Goldfish are good choices for indoor aquaria, but unless we're talking about an indoor pond, Koi really aren't an option. Cheers, Neale.>
Re: Koi Help (RMF, any tips on Koi indoors?)
Thank you for your response.
<Hello Alice,>
The reason I have the 3 Koi in an aquarium is because my husband died 4 years ago, and at that time I lived in a much larger home and we had over a hundred Koi in 3 large ponds.
<Sounds lovely.>
It broke my heart to give them away when I moved, and I couldn't part with the last 3 that he bought.
<I fully understand and sympathise.>
I realize they belong in a pond, but no longer live where that is possible.
<I see.>
The other 2 are fine and I truly want to try and make the Koi I have discussed well. Are you sure there is no way to accomplish this. Any suggestion would be greatly appreciated.
<In the short term, yes, antibiotics will treat Finrot (raggedy fins, sore/bloody patches on the body), and anti-fungal medications will treat Fungus (cotton wool threads). But if the environment basically isn't
healthy, it won't be long before these fish get sick again, with genetics perhaps playing a role too, the "weakest" fish being the one that gets sick first. A larger filter will make this aquarium more viable for longer, so adding a very large external canister filter for example might be an option. But three Koi in 75 gallons is never going to be easy. I'm sure your husband told you enough times that Koi are princes among fish, and need to be treated like the royalty they are. They're very special, very intelligent, and very long-lived animals. Yes, they thrive on love, which is one reason we like keeping them, but they also need the right living conditions.>
I have 3 aquariums in my home, the other 2 having small goldfish. When I have a problem with 1, I always look at your answers to others pertaining to whatever problem a fish may have. I have learned a lot from your website.
<I'm glad we've been able to help.>
Hopefully, you can offer a solution for me. I truly want to keep the Koi.
<Here's an alternative. Try and find a fish or Koi club in your city. Zoos and botanical gardens might be worthwhile too, as these often have Koi pools. It may well be that you can find an experienced Koi-keeper who can come take these fish and give them a more comfortable retirement. One way of looking at the situation is to see these animals your husband loves, but for one reason or another, aren't enjoying their life. It's much the kindest thing, and perhaps the more honourable thing, to rehome these fish someplace nice. In the meantime, you say you have someone fixing up the tank every three weeks. Feel free to pass on our e-mail address to them, and they can discuss their ideas with us if needs be.>
Thank you.
<Hope this helps. Cheers, Neale.>

Koi Not Eating and Sitting on Bottom (Fenner-san, any Koi wisdom to share here?)<<Nada>>    9/8/10
Hello Crew,
<Hello Benjamin,>
I have the following situation:
125 gallon aquarium
2 Eheim Pro II Canister Filters
Water quality checks out normal
5 Koi living in the same tank for 3 years. No additional plants or critters added.
<Well, you should at least be adding pond plants that your Koi can eat; these fish are herbivores, and a strict diet of pellets doesn't do them much good. In ponds they'll be eating algae and sifting organic detritus, so it's less of an issue. In aquaria, you really need to watch this aspect.>
4 Koi are active and eating just fine.
5th Koi which is very fat is not eating and sitting on the bottom. It started about 2 days ago. No visual signs of disease, with the exception of fins being clamped and it seems like it requires effort to swim up from the bottom. The anus/vent region also appears to be larger then normal. Is it possible the fish is constipated or egg bound which would cause this behavior?
<Constipation could certainly be an issue. Read here:
Any thoughts would be appreciated.
<More generally, a 125-gallon tank is insanely small for Koi. Let's be crystal clear about the fact Koi do poorly in aquaria anyway. They don't even do well in small ponds! So unless your aquarium is 500 gallons upwards, Koi are not going to be easy to keep, if viable at all. So general issues with improper housing could very easily be to blame here -- non-zero nitrite/ammonia levels, nitrate levels above 20 mg/l, insufficient space for exercising, and so on. I'm not a huge fan of keeping Koi or Standard Goldfish in aquaria, to be honest. Cheers, Neale.>

baby Koi    9/7/10
I'm hoping you can help me I have a 10ft pond with Koi I have just starting in the Koi side, a few months ago I got some baby Koi 3-4" and put them in my pond, time went on and things were ok suddenly one day they died day by day and was left with one, I brought a fish tank as well as some other baby Koi and put them in since putting the small Koi in the tank they are swimming around like mad they are in a 2ft long by 1 ½ foot tall tank there is plenty of room ( I think) roughly 9 of them the temperature is between 20 � 22c it has a sponge filter
<Mmm, not likely able to "keep up" with metabolite production here. Do monitor ammonia, nitrite...>
and a air stone in there they are feeding ok on crushed up tetra pond sticks but like I say they are swimming like mad is this normal as I don't really want to lose these ones I look forward to your help
Many thanks
<? Re? Please read here: http://wetwebmedia.com/PondSubWebIndex/pdenvdisdiagf.htm
and the linked files above. Bob Fenner>

Just a few questions'¦ (Bob, thoughts on Koi indoors?) 8/9/10
<<Can work, given space, good water quality as you relate... but not long term in aquariums. RMF>>
As you can see from the subject I have a few questions that I'd like to throw into one email to prevent my from bugging you later on :) I did some searching with the Google thing at the bottom of the pages but only found
the answer to one of them (the questions).
<Fire away.>
First off here's some info on the tank. It's a 250 US gallon monster (freshwater) with 2 canister filters and 2 powerheads. I did a 50% water change yesterday and forgot to test afterwards but the pH beforehand was 8.4 (I don't know if I should lower it as all the goldfish seem pretty happy).
<Sounds fine. The tank is big and Goldfish like alkaline water, as do many other kinds of fish. Hard, alkaline water is actually very good for fishkeeping, provided the fish you choose enjoy it.>
Nitrate was about 20ppm and nitrite was at .5ppm.
<This nitrite level is not good, and potentially stressful in the long term. Either the filters aren't mature, they're not properly maintained, the tank is overstocked, or you're overfeeding. Possibly a combination.>
The test kit also tested hardness and alkalinity which I have written down somewhere but the paper isn't very easily accessible (not in this building). It's inhabitants are: 4 "feeder" goldfish, 4 large common goldfish, 2 Koi, 2 Orandas, 1 Shubunkin, 1 fantail and 2 Plecos all of which I have had for roughly 2 months except for one of the Plecos which I have had for 1 month.
<That's a lot of potentially very big fish. You don't mention their size.
Ultimately, even 2 adult Koi could overwhelm a tank this size.>
My first question is will my Koi outgrow this tank when they (and all the other fish) get to be full size?
<Yes, they will. Koi are not really indoor fish. For Goldfish, allow 20 gallons for the first specimen and another 10 gallons for each subsequent specimen. You have 12 specimens, so that's 20 + 10x11 = 130 gallons for the
lot. Another 20 gallons for each Plec, that's 170 gallons if we're being generous, and over 200 gallons for the lot if we're realistic. Without the Koi, you should be okay, but honestly, with the two adult Koi, I think you'll be pushing your luck.>
If they will then I'd like to get rid of one or both while they can still be netted. They've grown 1" maybe more since I first got them 2 months ago and eat like little pigs. I tried searching this one but all it brought up was some info on Koi breeding, Koi outgrowing 55 gallon tanks, and kinked backs.
<Indeed. Koi just don't do well indoors. They've been domesticated for hundreds of years as pond fish, and that's what they are.>
Second, I read some info on Plecos from your site (maybe?) and discovered that keeping 2 Plecos in one tank is a really, really bad idea.
<Yes, or at least, two males can be extremely aggressive, and males attacking females is not unknown.>
If this is true than I'd also like to get rid of one while they're still somewhat small and there's still jars and bags big enough for them to fit into (3" and 6").
<Sometimes they get along fine, and in the wild they are schooling fish. So for now, watch and observe. But if you see signs of threatening behaviour, or worse, damage to one another's fins or body, then separate them. There
are reliable stories of Plecs killing one another if they're forced together as sexually mature adults.>
Third, my Plecos seem to be eating the paint off of 2 of my decorations.
<Yep. Doesn't seem to do any harm, but is annoying.>
The paint is gone in patches on one of them and on raised areas that they can get to on the other one (fake tree). I noticed this a while ago but didn't think much of it (oops?) and it was brought to the front of my mind when the larger Pleco was sucking on the shark thing and I noticed bits of paint gone. The Plecos seem to be attracted to these two decorations and will come back and ignore all the other ones.
<They're foraging for algae, and to some degree consume indigestible matter such as wood as part of the normal diet. I'd throw in some bogwood and let them eat that instead. Certainly ensure there's always something vegetarian for them to eat: carrot, potato, sweet potato, cucumber. With luck, they'll ignore the ornaments.>
Should I remove them (the decorations)? Also, I have another decoration in which air bubbles are forming under the paint. The paint doesn't seem to be coming off though. Should I remove that one?
<You can if you want. If good quality ornaments, the paint and the ceramic/plastic they're made from should be non-toxic.>
Fourth. About 2 days ago, I was watching my fish when their aquarium lights were turned off and saw my red, 2 1/2" Oranda scratching himself on the gravel. He did that twice and went back to sleep. A few minutes later, one
of my Koi came along and did the exact same thing in the same area. Then he swam a little ways and scratched himself on a nearby fake log. Upon visual examination with the lights on, I found nothing strange and (again) thought nothing of it. Yesterday, I was watching my fish again and noticed the same Oranda go up to one of the filter output spray bars and scratch himself against that repeatedly. The spray bar hangs vertical in the water since I can't get it to hang any other way. I looked over him again and found nothing. However, a few minutes later he began swimming erratically and in short bursts when he suddenly swam straight up and jumped out of the water.
This is where I did the water testing and the 50% water change. He behaved normally throughout the duration of the water change but after that when I was sinking a few flakes, he decided he wanted to bump up against my
fingers until I "petted" him. I decided to try something and lowered my hand into the water and he swam halfway onto it and began nipping until I "petted" him again. And this is the point where I got concerned and decided
to add this onto my list of things to contact WWM about.
<I think this is a reaction to the non-zero nitrite level. Fix the water quality. Nitrite and ammonia irritate the gills, and the reaction of many fish is similar to that of parasitic infections -- they jump, splash, and scratch seemingly wanting to scrape away the parasites. They don't know there's no parasite, all they can feel is something tickly on their gills.>
Later that night I gave them their second official feeding of the day (which is a rather tiny amount) and he ate his fair share and begged for more. He doesn't have anything wrong when I looked him over. However, his tail has gotten kind of opaque and has a "fuzzy" looking texture to it but there's nothing really on the tail. The white and orange parts have just gotten foggy and his "stomach fins" are normally red fading to a white and today those fins have turned completely white except for the base and the fin rays(?) when the red and orange typically were. His
dorsal fin is still perky.
<Again, I think this is the early stages of what can become Finrot. Fix the water quality, and if you want, use a mild anti-Finrot medication like Melafix or Stress Coat as a preventative against anything worse.>
Sorry about the really long message. Thanks for taking the time to read all of it.
<Happy to help, Neale.>
Re: Just a few questions'¦ (Bob, thoughts on Koi indoors?) - 8/10/10

Hi and thanks for the reply, Neale.
<Most welcome.>
On the sizes of the fish, the feeders are about 1"-1.5", the larger ones are about 3", the Orandas are 2.5" and 1.5", the Koi are a good 4"+, the Shubunkin is about 3.5", and the fantail is 1.5".
On the Koi, are you saying that my best bet would be to get rid of them?
<As both Bob and I stated, Koi generally do poorly in aquaria. May be fine for a year or two more. But the fact you have a non-zero nitrite level won't be good for them even now.>
I don't know anybody who has a pond and I'm not sure if the local pet store will take them back since it's been so long (and I lost the receipt) and I don't want to ship them anywhere out of town. For the nitrite level, I was gone for a few days and I think my brother overfed them because the water was cloudy when I got back.
<May be so, but assuming you do a decent water change and check the filter is working properly, any overfeeding should have worked itself though by now. If you still have non-zero nitrite levels by the end of this week, you have a problem.>
The Plecos seem to avoid each other unless there's food at stake and the big Pleco usually scares off the little one.
I drop half a slice of zucchini in the tank. Everything vegetarian seems to float into the unreachable parts of the tank and I end up tying it to one of the decorations which the fish end up knocking over.
<Lettuce clips work great, and I use strips of lead weight -- sold for tying down aquarium plants -- to hold down zucchini, carrots, sweet potato and lettuce stems.>
What would be a good thing to use to weigh it down instead and how long can/should I leave a vegetable in the tank before taking it out?
<No need to remove vegetables, though for cosmetic reasons you can slurp up debris using a hose and bucket.>
Once again, thanks.
<Cheers Neale.>

Butterfly Carp, in an aquarium, injured likely    1/13/10
Hi Crew,
Sorry to bother you again. Actually my butterfly carp's two scales are bleeding and something is coming out of them. Is it a great threat for my fish. I am sending the video clip because I was not able to capture its image. Please tell me what can I do? ;-)
<Can't make out what "is coming out"... but otherwise this looks like a physical injury (a trauma). Could this fish have damaged itself on some decor (a sharp rock for instance)? Unless you can identify the presence of a specific pathogen, parasite, I would not add any curative, medicine here.
The fish appears otherwise active, healthy, and should heal on its own. Bob Fenner>

Koi w/Fin Rot  12/27/09
<Hi Alice.>
I have 3 Koi's in a 75 gallon tank.
<How large are these fish? This is a very small tank for 3 Koi. What type of filtration?>
One of the Koi's developed what looks to be fin rot-white edge on one side of fin that tears, turns white again and tears. It has loss to where the other fin meets in a point. Also, the mouth developed a white growth on each corner. The fish is still active and eats.
<This is a good sign.>
Someone maintains my aquariums and told me to use Melafix for a week, which has not helped after several treatments.
<Finrot is generally caused by poor water quality, Alice. The reason that the Melafix isn't working is that it's not a strong medication -- some even say that it is virtually useless -- compounded with what caused the problem in the first place -- poor water quality.>
Now I have been told to treat with Seachem Metronidazole.
<This medication is commonly used to treat protozoan infections, not Finrot. So, it's not the right thing to use, anyway. I would recommend Maracyn, but not until you've taken the steps to ensure water quality is spot-on.>
Haven't started because I was told the risk to my fish is high ammonia levels.
<You're right. Medications can disturb the biological cycle, and over- or mis-medicating can stress and kill fish.>
In a real panic and don't know what to do to cure my fish and not hurt the others. Can't set up a hospital tank.
<This shouldn't be necessary, as fixing water quality will likely fix the sick fish. However, if this becomes necessary, a "hospital" tank can be a big Rubbermaid tub with a sponge filter -- no need to go all out, really.>
Noticed you ask some about the various levels, but since I have someone else maintaining the aquariums I would not have that information.
<I would obtain it for a few reasons. For one, these are your fish, and you care about them more than anyone else ever will. Therefore, you've got to be the one making sure that they're being treated well. Another is that this once-monthly cleaning probably isn't enough, and the numbers gained from Ammonia, Nitrite, and Nitrate tests would indicate if this is so. Yet another reason is that I assume that you're paying this person to care for the tank; if they are really doing what they should be doing, providing this data should be no problem. The fourth reason is that the fish is now sick, and you're the one having to fix him, not the caretaker. So, you need to take the informed approach and understand what's going on. The fifth is that these aren't fish for a 75-gallon tank, and there's going to be a point at which their environment will need serious upgrading. Those numbers, once you understand what they are and what they mean and how they relate to one another, will help you decide when it's necessary.>
Tank is cleaned every 4 weeks.
<This is likely not enough for 3 Koi. Bi-weekly water changes are really a must with these large, messy fish.>
Please help me save my fish.
<You'll need to get those numbers in order for any decision to really be made. If they're off, water quality will have to be fixed before any fish gets better, and fixing them may result in the fish healing on its own. If they're not, then that's the green flag to go ahead and medicate. If this is the case, a hospital tank would be the best step. Obviously, this would be a silly thing to do if the problem is water quality -- thus, the reason for figuring that part out first. Please take a look at the following links, and feel free to write back if you need any more help:
http://www.wetwebmedia.com/FWSubWebIndex/fwestcycling.htm (and the linked files below the title)

Re: Koi w/Fin Rot 12/29/09
Thank you for your information. I have also looked at the websites suggested.
<You're welcome.>
 My husband died 3 years ago
<I'm sorry to hear.>
 and we had 3 large ponds with over a hundred fish.
 When I moved I found them good homes, but wanted to keep a few of his Koi. They
are not that large yet.
 Also, have 2 other aquariums with goldfish that are doing fine. The girl who maintains my aquariums works at a local fish store and I took a sample of water today and was only told, the water is fine.
<Yes, but what is "fine?" The reason this is SO important is that these problems are coming from somewhere! We have to figure out why they showed up in order to make sure the fish heal.>
 My fish is still active, but the fin rot and the white growth at corners of mouth has had no change.
<I am glad the fish is still active.>
 What do you think the problem with its mouth is? Failed to mention Maracyn was the first treatment used.
When this didn't work, Melafix was suggested. Neither has worked.
<Okay. When you used the Maracyn, did you complete the treatment? This should have taken care of both problems. The Maracyn should have done something -- in my experience, this is a medication which usually yields results. This is why I'm worried, and I really, really want you to take charge of this water testing thing. You might have to actually say, "It's nice that it's fine. What are the numbers?" Or, just buy the tests so you can have them for your own usage, interpretation. The test kits are really simple to use, so don't be worried about that.>
My filter has 2 bio-wheels.
<Okay. So, your filtration may not be up to par for these fish. This sounds like a large hang-on-back filter, but you're really looking for filtration that turns the tank's volume over 8 to 10 times, and especially with Koi. Another reason those numbers would really help. What you can do to attain this type of turnover is, say, add a large canister filter in addition to your hang-on-back.>
Took the carbon filter out to treat (24 hours ago) and used the Seachem once, feel that I should put it back, to not risk poor water conditions and will not use the Seachem again.
<Okay. That's fine -- I don't think this is among what you need to be treating with anyway.>
 Today I was told that she doesn't want to be responsible for killing my fish and is afraid if we keep trying, its
<Well, that's a crazy answer. What does she think will happen if you don't treat the fish? Either way, why won't she provide you with the numbers you need?>
How do I restore the fin or keep the fin from getting worst and I have no idea about the mouth. Will definitely schedule bi-weekly on this tank.
<I'm glad to hear that. I really think you should buy some test kits and test that water yourself, Alice.>
It will hurt so much to lose his fish.
<This is why you should go ahead and buy those test kits, I think. As I said in my earlier e-mail (without knowing any of the context here), you care for these fish more than anyone else ever will -- why leave the big decisions to anyone else?> With the various medications, is it possible it will heal in time?
<Yes, this can heal. But, we've got to start at the beginning -- let's get those numbers. Let's figure out why this started in the first place. If those numbers reveal water quality to be spot-on, then you know you can treat, and see results. But, if you ran the entire course of the Maracyn and saw no change, I worry that there's something going on with water quality. The Maracyn should have worked on both of these. I'd like to include this:
http://www.wetwebmedia.com/fwsubwebindex/fwfishmeds.htm because I think
that, after we ensure the water is what it should be, another round of treatment is in order. I hesitate to recommend Maracyn again without knowing why it didn't work before. So, you should be able to take this list and determine what is available to you at your LFS. There are some other Mardel products, such as the MarOxy, that you could try. Please, though, don't treat without first trying to determine why this occurred -- it's really important that we figure that out, or the fish won't heal properly, and worse, your fish will be open to having this happen again in the future.

Butterfly Koi; indoors    11/3/09
Hello I have a 180 gallon aquarium (8ft long) and would like to know if i could keep butterfly koi?
<Depends what you mean by "keep". Will they live in such a tank? In theory, yes, given adequate space and very generous filtration (we're talking at least 8 times the volume of the tank in turnover per hour) Koi Carp can be kept indoors. However, very few people are able to provide the conditions they need as indoor fish. I'm a bit confused by your aquarium being 8 feet long and yet only containing 180 gallons. Let's say this tank is 8 x 3 x 3 feet, that's 72 cubic feet in total, or 538 gallons. So something's amiss here. A tank 8 by 2 x 2 feet would only be 32 cubic feet, or a mere 240 gallons, but you can't keep adult Koi in tanks two feet wide since they get to more than two feet in length! So you might want to go back, measure your aquarium, and then ask your question again. A 538 gallon tank would be acceptable for Koi, being essentially an indoor pond, though you would need massive filtration. Whenever I've seen Koi kept indoors successfully, by
which I mean they reach full size and live a normal life, they're in an indoor pond coupled to a pond-grade filter system. Now, I'll also make the point that on the whole Koi aficionados tend to look down (being polite here!) on Butterfly Koi. They are not acceptable at Koi shows for example, and they cannot be graded (which, among other things, means the quality of Butterfly Koi varies wildly, and as with anything in life, you often get what you pay for. Butterfly Koi are essentially absent from the trade in Europe and Japan, and are really only popular in the US, where tastes are somewhat different ("less snobby" or "less discerning" depending on your point of view). What I'm saying then is that Butterfly Koi, like all Koi,
are extremely demanding when kept indoors -- they're pretty demanding kept outdoors, too! -- and without any sort of quality control, it's all too easy to end up with fish with congenital defects, poor disease resistance, and so on (think of puppy mills in terms of dog breeding, and apply that to breeders cranking out Butterfly Koi). Do your research, budget carefully for the needs of the fish, and take some time to locate a reputable breeder of Butterfly Koi who can supply you with good quality fish. Cheers, Neale.>
(RMF, what do you think of these long-finned fish?) <<As time has gone by, I've "gotten used to" this variety, and it is indeed included in some Koi shows here in the U.S. nowadays. However, not "my cup of tea". BobF>>

Goldfish has dark red spots and looks like missing scale (RMF, any wisdom to share here?) 4/15/2009
I work in Afghanistan on a military base.
<Ah, not a part of the world we get many messages from...>
I purchased a small (5.5 gal) desktop tank on the internet.
<OK; but do be careful, these small aquaria really aren't terribly useful;
do see here:
My local national employees brought a goldfish for me from a 'pet store' in Mazar-E-Sharif. I have had many fish in the past and I would say it is not a true 'comet type' goldfish. It is probably some type of river fish.
<Perhaps a wild carp of some sort? Or a minnow? A photo would be both fun and useful!>
I do weekly water changes with bottled water.
<As in drinking water? That should be okay; but don't use deionised or distilled water, as that will quickly sicken your fish.><<Actually... the system size, this water... are likely the sources of trouble here. RMF>>
Recently my fish developed dark red spots (like boils) on the sides and it appears some scales may be missing.
<Does sound like Finrot or some other type of opportunistic bacterial infection.><<Environmental in origin. RMF>>
I have no access to any products (other than the internet) so I am looking for a home remedy.
<Unfortunately there really aren't many reliable remedies for bacterial infections beyond the use of drugs. The addition of salt, for example, can help under some circumstances (3-10 gramme per litre) but it's not
reliable. It's drugs like Nifurpirinol (0.1-1 milligrams per litre) and Oxytetracycline (20-100 mg/l) that are used most successfully. Failing that, certain organic dyes and other chemicals can work: Malachite Green
(0.1-0.5 mg/l), for example. A vet or MD may be able to obtain these for you. Do note though that since these infections are opportunistic, caused by otherwise "good" (or at least harmless) bacteria, if you don't fix the root cause, usually environmental conditions, the fish won't get better.>
The fish has become more lethargic but seems to be breathing normally.
Every couple of days I put a small amount of table salt in the water. Do you have any suggestions?
Thank you,
<Done my best.>
<Hope this helps, Neale.>

Re: Goldfish has dark red spots and looks like missing scale (RMF, any wisdom to share here?)
Hello Neale,
I appreciate your quick response. I know the small tank can cause problems. I could not find any dealers online that would ship a larger tank to an APO address.
<Ah, I see. Unfortunately, science isn't all that flexible! If a fish needs 30 gallons, it needs 30 gallons. I'm mindful of the issues when governments set fishing quotas as an example. The scientists say the population is only so big, and the fishermen can tank X fish per year if the population is not to go into decline. The fishermen say they need twice that number otherwise they'll lose money and jobs. The politicians, trying to split the difference and give everyone a compromise, choose some number between X and 2X. Sounds good on paper, but science doesn't compromise, and the fishery eventually collapses. In the case of an aquarium, you need a certain amount of water volume to dilute the ammonia and other wastes produced by a fish (or fishes) of a certain total mass. With small fish like guppies, this is where the "inch per gallon" rule comes from: you allow a gallon of water for each inch of fish kept. Likewise, you need a certain sized filter to break down those wastes quickly enough that the dilution effect of the water volume remains within safe levels. To cut a long story short, Goldfish need about 20 gallons when small, but 30 gallons once they're above a couple of inches in length.>
I do use bottled drinking water (see picture) for the water changes. The bottle lists the composition / mg in each .5 liter bottle: Calcium-16, Magnesium-16, Sodium-10, Potassium-<1, Iron-<.01, Bicarbonates-7,
Sulfate-3.5, Chloride-80, Nitrate-<1, Fluoride-<.01, Total Dissolved Solids-225.
<Should be fine. The pH is important though, Goldfish preferring a pH around 7.5-8.0.>
I have attached a couple pictures of my fish and copied my wife on this response. She would be able to go to a store in Wisconsin and send me the products you previously suggested.
<That would be helpful.>
The mail takes about 1 week to arrive.
<Hmm... try adding some salt to the water as mentioned last time, but I fear this will be a rough week for all concerned. This fish (seemingly a Carp, Cyprinus carpio, rather than a Goldfish, Carassius auratus) has a bacterial infection of the type usually called "Ulcer Disease" or else Finrot of some type. It's essentially an opportunistic infection caused by otherwise harmless bacteria invading the body of a stressed fish with a weakened immune system. I really can't stress this strongly enough: the tank isn't big enough, and the conditions in the water are likely dire. No amount of treatment will help. Since this is a pond fish (Carp = Koi) perhaps building a pond is an option? A large plastic drum of some sort perhaps? Otherwise, to be completely honest, I'd painlessly destroy this fish and stock with something appropriate to a 5-gallon system. Perhaps some local Killifish? Of course, wandering off into Afghanistan looking for unusual aquarium fish might not be all that safe! But would make one heck of a National Geographic special!
Thanks again for your help and give an extra hug to everyone in your family for all those of us who are separated from ours.
Thank you,
Bagram Air Field, Afghanistan
<And good luck to you and all you do out there. Cheers, Neale.>

Koi in a reef tank   11/25/08
Hello all,
I live up in MN and have my 3 Koi in a tank in the house for the winter. It is a bare bottom with nothing in it. I have a lot of fake and dead coral pieces. I was thinking it might make an interesting tank to put the coral pieces in the Koi tank. Will this negatively effect my water parameters and cause an unsuitable environment for my Koi? I do not want to harm my Koi but want to make their winter home a little nicer.
<Hello Walt. Fake coral obviously has zero effect on water chemistry, and should be just fine in any freshwater tank. As for dead coral (something I'm sure Bob Fenner will agree is not something we encourage people to buy, because of the way it is collected) then if you happen to have a few bits, by all means add to a tank containing hardwater-tolerant freshwater fish. Koi prefer hard water to soft, so this isn't going to be a problem from that angle, provided the pH doesn't go much above 8.0 and the hardness isn't much above 25 degrees dH. However, coral is "scratchy" and big, clumsy fish (like Koi!) may find themselves damaged if kept in a relatively small habitat like an aquarium. It all depends on the size of the tank compared with the size of the pieces of coral. If it's a 200 gallon tank and the lumps of coral are the size of your fist, then adult Koi are unlikely to come to any grief. But in a 55 gallon tank, with corals the
size of your head, then things could be different. Cheers, Neale.>

Re: Koi in a reef tank   11/25/08
Neale- thanks for the response. I agree dead coral is something to avoid but it was given to me many years ago and I never used it in my FOWLR.
<Cool. The reason I mention things like this is not necessarily for you, but for other readers browsing our site. In the UK (and indeed the EU generally, I believe) dead coral cannot be traded at all, and I'd like to encourage people around the world to generally avoid buying the stuff. Live corals are one thing -- they have to be collected carefully -- but dead corals are relatively cheap, and there's little incentive to collect them sustainably.>
They are small Koi 2 3" and 1 6". I was only going to use the smoother corals as I am not sure which are fake and which were real.
<Ah, I see. You should be fine. Koi are such special fish that it is ALWAYS worth taking extra care when housing them, especially indoors. The benchmark with Koi is high (in my opinion) because it's decades before they really develop their full potential. They can also be incredibly expensive, even the "bargain" Koi being relatively pricey fish.>
I am going to add a couple pieces and see how it looks.
Thanks again,
<Good luck, Neale.>

Transferring fish... Koi, goldfish... in a 55?  6/25/08 Hi! I recently purchased a 55 gallon aquarium (last Sunday) The Goal is to put 2 Koi and 2 black moors which are housed in a 20 gallon tank into the new 55 gallon tank. I have put 2 gallons of water from an established 10 gallon tank. <Water contains almost no filter bacteria, so adding water from one tank to another doesn't do ANYTHING to speed up maturation.> 5 gallons from the 20 gallon tank added cycle brand live bacteria as recommended. I also took the old filter from 20 gallon tank and cut off pieces of it and threw them into the 55 gallon. <The good news is that "old" filter media will instantly mature a new aquarium (if used in sufficient quantity). By contrast, potions like 'Cycle' tend to be a bit hit-and-miss in efficacy.> The 55 gallon has been running since Sunday. <If you have matured the aquarium with filter media, remember: those bacteria can starve. ALWAYS add sufficient ammonia or fish food to keep them happy. A couple of pinches of flake work great. As the flake decays, it produces ammonia, and that feeds the bacteria.> My question is this... How long should I wait before adding the fish? <Don't. Add fish right now. The old filter media will have matured the new filter, assuming the water chemistry is similar between the systems. You can take 50% of the media from a mature filter and put into a new filter. The old filter will carry on working fine, and it will mature any new media put into it. The new filter with the old media (confusing, I know) is effectively a mature filter now! This is called "cloning" a filter, because what you're doing is splitting one mature filter into two mature filters. It is BY FAR the safest and quickest way to mature an aquarium.> The pet store told me to get a few tiger barbs to help with cycling but I don't want any more fish!! lol <Rubbish advice.> I am extremely attached to these 4 fish and don't want to harm them in any way. I am afraid to move them to their new home too soon. Any advice you could give me would be very appreciated. <Do an ammonia test. Even with flake adding to the water, you shouldn't detect any ammonia 24 hours later. This is because the bacteria hitch-hiked from the old aquarium into the new aquarium on the filter media you moved into the new filter.> Oh, also the tank came with a whisper 60 filter (hangs on the tank) I was thinking to be on the safe side to add another whisper 20 on the other side? Thanks Oh by the way, I didn't add any used gravel because I went with a different color in the 55 <Do remember fish can't stand brightly coloured gravel. If you want happy fish, especially goldfish, choose fine gravel or even better smooth silica (silver) sand. Don't use too much or they'll make a mess, and you won't be using live plants so a big depth of substrate isn't important. Cheers, Neale.>

Re: transferring fish -- 06/26/08 Thanks for the information. (I feel really stupid now...lol) When I did the filter I was unaware that I was supposed to take the inside (charcoal) out of the old filter. <You don't have to. Old charcoal is simply biological media by another name; it no longer removes dissolved organics. Carbon only removes organics (the yellow stuff in the water) for about 2-4 weeks from brand new. Unless you're replacing it every 2-4 weeks, it isn't doing anything other than supporting biological filtration. Hence my usual advice to freshwater aquarists to skip the stuff entirely in favour of high performance biological media such as quality ceramic noodles or sponges.> I just cut off the dirty cloth stuff and threw it into the new filter (duh! My Bad!) <The sponge in the old filter is precisely what you want; the think cotton cloth stuff is likely the pre-filter, and of no particular value or harm. It is meant to replaced every month or two, the idea being it catches solid waste (e.g., dead plant fragments) leaving the biological/chemical media free to react with the water.> Problem is that now the old filter was thrown away and new one put in the 20 gallon tank on Sunday. What should I do now? <Not sure what you're asking. If you've put sponge, ceramic noodles, or even "old" carbon from the old filter in the new filter, then the new filter will almost certainly be biologically active. If you have done none of the above, and only used aquarium water or a bit of gravel from the old tank to "seed" the new filter with bacteria, you actually haven't done any such thing, and the tank will need (at least some) cycling. In any event, you ammonia or nitrite test kit will help here: if you detect either, then you have a filter than needs cycling. If you have zero ammonia/nitrite, then everything is fine. Test kits beat theory! Cheers, Neale.>

Bent tail, Koi in tank, using WWM   4/16/08 I have 2 Koi in a 55 gal. D.A.S. tank. <Will outgrow this in time> Water is fine. One of my Koi started to get a little kink in his tail, but everything was fine (swimming, eating) It has gotten worse. His tail is bent up (almost in a "V" shape) and now is not eating and is laying on the bottom. Has been this way for a couple of days now. He is struggling to survive, so I am trying to help him. Thank you Charity <Mmm, well, such bent tails can be a manifestation/expression of genetic anomaly, nutritionally derived, environmental (too small quarters), or pathogenic in origin... See here: http://wetwebmedia.com/WWMAdminSubWebIndex/question_page.htm put the term "bent tail" in the search tool, read the cached versions Bob Fenner>

Sick goldfish... and Koi, env.   2/29/08 Dear Bob I had a 15cm Koi and comet in a 1 metre tank. Koi suddenly died for no apparent reason overnight and the comet who was silver started turning pink and the edges of his back and tail seem to have what looks like bleeding veins as though he is bleeding internally. I've had him for 7 years without any problems. Can you please help?? Sincerest and heartfelt thanks Pearl in Australia <Hello Pearl. The problem with the comet is almost certainly Finrot. The symptoms here start with congestion in the veins of the fins as the bacteria set in (that's the pink stuff you see) followed by the tissue dying (goes white) and then eroding (so the fins look ragged). Finrot itself is almost always caused by water quality problems. Perform (at the very least) a nitrite test. Check the filter is working properly, and regardless do two 50% water changes today (a couple hours apart) to flush out some of the pollutants. Stop feeding the fish. Being treating with a reliable anti-Finrot medication (remember to remove carbon if present in the filter). Melafix/Pimafix aren't my recommendation for this, although often sold as such. Use a decent copper-based medication or antibiotic. Koi really aren't indoor fish, and certainly can't be kept in a 1 meter tank -- I'm guessing that's about 180-200 litres/40-50 gallons, which is adequate for Goldfish but not Koi. Koi are simply too sensitive to poor water conditions. Cheers, Neale.>

My Oranda fish lost it's eyes  -02/20/08 Hi guys, I searched the site but couldn't find my answer. My Oranda fish is the only Oranda in a 55 gallon tank along with 3 goldfish and a Koi. Three weeks ago I noticed one of my Orandas eyes missing and now today another one. I have seen all the fish at one point or another pick at his fins but, HIS EYES? Why do they do this and can he survive like this? Will the others continue to pick at him? So concerned! Thanks Concerned new fish mommy! Have a wonderful day! Jessica <Hello Jessica. Eyes are -- after fins -- the bits on a fish easily damaged by fighting. So the best thing a "concerned fish mom" would do at the first signs of aggression between fish is to separate them so this couldn't happen. It is unusual for goldfish and/or Koi to be aggressive towards one another, but they can be boisterous, and it is ALWAYS recommended that fancy (double-tail) goldfish are kept in different tanks to single-tail goldfish and Koi. In other words: Orandas, moors, Ryukin, etc. should all be kept in different to tanks to plain goldfish, comets, and Shubunkin's. I'm guessing that you didn't do this. If you didn't, you know now! As for therapy: treat with an anti-Finrot/anti-fungus medication first, to prevent a secondary infection. Do also check the water quality, specifically nitrite, to see that there isn't a problem there. It is entirely possible that minor damage (that could have healed) quickly turned bad because of poor water quality. There should be zero ammonia and nitrite in the system. In addition, check water chemistry for the same reasons. Goldfish need hard (10+ degrees dH) and basic (pH 7.5) water conditions. Will the eyes grow back? Obviously not. Can he live without them? Yes, provided he is kept alone. He will navigate using his lateral line and forage for food by touch and olfaction, but the goldfish with eyes will be able to out-compete him at feeding time. The result will be a lot like dinner time at the home of Phineas. Cheers, Neale.>

Some Koi Flashing but not All  2/1/08 Hello, <Hi there> I have a 125 gallon tank with 9 fish in it, 5 Koi, 3 Comet and 1 Fancy Comet. <I see them in your pic... a bit crowded physiologically> Sometimes especially in the evening once the lights go off on the tank, a couple of the Koi will flash, turning to their sides and making a swift rub on the bottom. I will also notice sometimes that they flick their fins rapidly as if something is bothering them, but upon visual inspection I see nothing. <Mmm, there may be naught> I have treated them for parasites with Jungle Labs Parasite tabs, added some salt to the tank, and I do regular water changes daily, about 20 gallons, during which I grab most of the waste off the bottom of the tank. The tank has 2 Eheim Profession II 2080 canister filters on the tank. Further, the fish that do flash do not appear to have any open wounds or irritated spots. When I have done water quality checks, the ammonia, nitrate and nitrite levels all appear zero... only the ph seems a little high at around 7.8. The tank water fluctuates from 67-69F depending on the time of day. <Brrrrrr! You keep your home cool> So what I cannot figure is, what is the problem? Or am I just paranoid? <Mmm, perhaps cautious... but unless you have introduced (through plants, new fish, live food) some new parasite/pathogen, there is likely nothing disease wise wrong here> I attached a picture of the setup. Regards, Benjamin Schmaus <I would cut back on these fishes feeding... they're apparently "fat"... Cheers, Bob Fenner>

Re: Some Koi Flashing but not All   2/8/08 Hello Bob, <Ben> So the swollen eyes went back to normal on that one koi and he is also eating again. However he still flashes now and again I read the following: General Hardness influences Calcium levels in the blood, and the osmotic regulatory systems of fish are affected by concentrations of dissolved salts. High levels could irritate gill membranes, they may look slightly swollen, and the fish may be seen flicking or rubbing in the water. <This is so> My GH is around 180ppm which is rather high. Could this be contributing to my fishes behavior? Maybe one is a little more sensitive? <Is possible... though all koi, most all fishes... do flash to a degree... I do think you and this Nishikigoi are "out of the woods" at this point. I hope this metaphor means that it will be okay. Cheers, BobF> Benjamin Schmaus

Re: Some Koi Flashing but not All   2/3/08 Hello Bob, <Good day Ben> Thanks for the response. So other then a cold basement and fat fish, there should be no worries on the flashing. Like I said, it happens fairly rarely. <I wouldn't be concerned> You are correct that it is a bit crowded. That will change once spring arrives and I can place them back outside in their summer home. I attached a picture of that location as well. Regards, Benjamin Schmaus <Ah, good. BobF>

Re: Some Koi Flashing but not All  2/4/08 Hello Bob, <Ben> Here is an update on one of those fishes that was flashing... Today I noticed that the eyes were bulging more then normal and when I fed them, the koi would take in food but then spit it back out. There appears to be no sign of him being bloated or pine-coning. He also exhibits what one might call a cough. <Mmm, something apparently amiss> Water quality appears normal. Although PH might be slightly low, 7.0 side and water hardness is up there. No ammonia, nitrites or nitrates. The only thing that changed from yesterday to today, was I replaced the fine filter pad in one of my Eheim's and also changed the charcoal. Both were rinsed in water before placing. <Mmm, but only the one fish affected... and only one pad, and no detected nitrogenous anomaly...> The other fish seem fine and all are eating. Regards, Benjamin Schmaus <If you had another system/tank up and going, I might move the one not acting quite right... Perhaps it (literally) swallowed a bug... BobF>

Lethargic koi, env. dis.  - 11/26/07 Hi Robert, <Carson> I have a small tancho koi that is about 4-5" that I am currently keeping in a community aquarium due because we haven't built a pond yet. It was purchased at the same time as a Kohaku koi that is currently 6-7". They were the same size when purchased. The past couple of days the tancho koi has been very lethargic and only really moves when you approach the tank. <Mmm, how long ago was this Nishikigoi purchased? What water conditions was it under at that time?> It doesn't seem to want to eat very much. The ammonia level is at .25 ppm, <Toxic!> the nitrite is the same, <Ditto. These MUST be zero> the pH is at 6.6, the nitrate is at 0. <You are fortunate here... if these values were higher the NH3... would be NH4OH much more... and deadly> The water temperature is at about 74 degrees f. There doesn't seem to be any spot of ich and none of the other fish are exhibiting any unusual behavior. The tank is 55 gallon with two filters (one sixty gallon one thirty gallon) that are constantly going, The tank consists of the following fish 1 - 4" tancho koi 1 - 6" Kohaku koi 1 - 5" comet goldfish 2 - 2" comet goldfish 3 - 2.5" bala sharks 1 - 3.5" golden shark 1 - 4" tinfoil barb 1 small freshwater crab. Their diet consists of flakes, freeze dried brine shrimp, freeze dried krill, and occasionally bottom feeder shrimp pellets. <I would cease feeding period till the ammonia and nitrite are zip, nada, gone> Is there anything that I can do to help my tancho koi? Carson L Maestas <... you should read... On WWM re water quality, environmental disease... Your livestock is in grave danger. Bob Fenner>

Carpet surfing Koi  11/28/2007 Hello guys, Last Saturday morning I found my Koi carpet surfing. I live in MN so he was inside in an aquarium with a full hood for the winter. He knocked the plastic lid off the hood. It was still dark so I found him by touching him with my foot.. Not a great feeling. Anyhow he was still alive so I drained some tank water into a bucket and placed a power head in the bucket and was able to revive him. He is back in the tank with the 2 other Koi and 2 goldfish. He is in very rough shape and lost a lot of scales and body slime. He is about 12" and was a beautiful bright white with orange saddle. He now looks orangey white especially on his head and the one side, I would assume that is the side he was laying on. Anyhow he is breathing the same as the others but not very active and has yet to eat since the incident. I have been adding stress coat to the tank in an effort to help. Also, the tank is not heated so the temp is around 66. Any suggestions to get him to eat? I am feeding them Koi food from Blackwater Koi Farm ( I am pretty sure that is the name). Should I heat the tank? Will that help him recover? Any other products to add? I added barley pellets in the pond would they help in an aquarium? I am running a filter with carbon right now. I also have saltwater tanks so would adding a little salt be beneficial to the Koi in the tank? Any suggestions to get him eat first and then all the way back to health would be appreciated. Thanks so much, Walt <Hello Walt. Your Koi will get round to eating precisely when he feels like it, and not a moment before. There's no real advantage to trying to speed this up. Koi can go weeks without food. So leave him be, and simply offer a variety of the usual foods you give them. Plant material like pondweed could be placed in the tank so he can have a bit of a graze if he gets peckish. Heating the tank won't really provide any advantage unless the tank gets very cold; 66 F should be perfectly tolerable for a Koi. Adding Stresscoat and salt may have a marginally positive effect, but for now I'd dose the tank with an anti-Finrot/Fungus medication just to make sure no secondary infections set in. This is the most likely problem, because the mucous and skin dried up, and they're the first line of defense for a fish. Naturally, remove carbon while treating the fish, and in my opinion, never replace it. Instead add more biological filter media and ensure you're doing substantial weekly water changes. Together these will greatly enhance the water quality, limiting the chances of secondary infections. Once that's done, the fish should make a speedy recovery. Good luck, Neale.>

Re: Carpet surfing Koi 11/28/07 Neale- Thanks for the quick response. I will pick up a few plants for him. Also what other fresh foods would you recommend? <Carp are, at heart, omnivores. Anything soft will appeal. Tinned peas, mashed prawns, bloodworms and so on will all be good. I find omnivorous fish often enjoy algae ripped out of a pond. They peck away at it for hours.> I think Zoecon is for Marine fish but would adding Garlic Xtreme or Zoecon to the food help? <Worth a shot. But Koi generally have very good appetites when they're healthy, and I suspect you'll find he'll take food once he's settled down.> I will switch to a medicated anti Finrot/fungus treatment and remove the activated carbon. I have been doing saltwater so long I am blanking out on a good biological for a freshwater aquarium. Do you have a good suggestion or a link to do some research? My pond pump equipment is too big for the aquarium. Would barley pellets help in an aquarium. They seem to really help in the pond. <This is for fixing algae, right? Not sure they've ever been used in aquaria. Generally, algae isn't a big deal in aquaria. Yes, you get algae on the glass, but scraping that off is so easy why bother with anything more complex? Green water -- that scourge of small ponds -- just doesn't happen in healthy aquaria. So I wouldn't bother with them.> Thanks again, Walt <Happy to help. Cheers, Neale.>

Re: Carpet surfing Koi   12/5/07 Neale Thanks for your efforts but He passed away last Friday. My wife called when she got home to say he was twitching on the bottom. When I got home he was not moving or breathing. I tried reviving but with no success. The sad part is he seemed to be getting a little better everyday. He must have been out of the water long enough to do permanent damage. Thanks again, Walt <Walt, too bad. Sorry things didn't work out this time. Good luck with the rest of your fish! Cheers, Neale.>

Curios.... ities... Stocking, not-stocking Koi in fish tanks... some goldfish   11/16/07 I was planning to buy a new aquarium and want to buy some Koi, or any Chinese type goldfish such as the lionhead. How many can fit into a 55 gallon tank? Fully grown I mean. Thanks for the help. <The short answer is 0 Koi carp and maybe 4-5 goldfish, depending on their type. Fancy goldfish tend to be less active than normal, non-fantail goldfish (i.e., plain goldfish, Shubunkins and Comets). Koi carp simply cannot and should not be kept indoors. They never do very well, and their large adult size (around 60 cm) makes them incredibly demanding in terms of water changes and filtration. If kept indoors at all, they need tanks measured in the 100s of gallons. Do also remember that fancy and regular goldfish cannot automatically be mixed. The really disfigured goldfish such as Celestials and Bubble-eyes have a hard enough time finding food and avoiding infections. So keep these sorts of fish on their own. Robust fancy goldfish though, particularly Black Moors, tend to be reliable tankmates for regular goldfish. Cheers, Neale.>

Please help =] Koi/aquarium maint.   11/15/07 Hello. I need some help and the web sometimes confuses me and doesn't really help me find my answers. <... You're not alone here. The "Net" is not designed to inform... but more to "chat", sell stuff... One must search for more informative sites...> So I was hoping you guys could. I'm helping my grandpa find a new filter or figure out what's wrong with his tank. He has approximately a 40 gallon tank and he has to clean it about every two days. He has Koi in there <Stop! This is "a/the" reason right here... the type of fish (ornamental carp) and a small volume... They're messy... really need to be in a pond> so he has to bring in gallon buckets of pond water when he cleans it. <Oh! You have a pond. This bringing water in is a very good practice> He says it needs some of the bacteria from the pond in there. He has 4 Koi in the pond. Right now he's using a Whisper 20-40 filter. <A good product> Is there a different filter he should use or is there something else he should do? <Mmm, are the Koi in the tank and not in the pond for a reason? I would add another outside power filter here... and perhaps a mechanical aerator (bubbler), but you will still need to change out a good deal of the water weekly. Perhaps a pump would help here.> I don't think he should be having to work that hard. Thank you greatly. sorry if this is confusing. <A small submersible pump... one that can be hooked up to a garden hose... and a shut off valve, ball type like for irrigation... at the end... will help in moving the water... The outgoing water can/should be gravel-vacuumed, placed on

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