Koi in the dark

[Stevo]

I have been keeping my koi in a heated garage for the winter the windows are blocked off no sun light and I really dont want to leave my 8' florsent lights on $$. Water temp is 60* and have been feeding well. Could this turn into a problem?? 

[Vickie]

I have no idea but I thought they need light. I have never kept any fish in the dark.

[marla]

I would put the lights on a timer so they get some light.  Even under the ice the sun will get through.

[Michiponder]

I keep koi through winter outdoors covered for often 4 months.  There is very little light penetrating these covers.  In the spring these fish are brilliant in color and healthy.  There is a big difference though, between your way of overwintering and mine.  The 60F temps are far warmer than mine which are as low as 40F.  Mine do not get food till spring either, but at 60F most people still feed at least some food.  I have kept fish indoors at higher temps for the winter, but without supplemental light thier colors often faded and by spring were far more dull than those kept colder.  In years past fish that were supplied with supplemental light during winter indoors were a little brighter, but still not as bright as the fish I keep outdoors.  Is it the winter fast, the cold water, or some other factor?  I do not know. I just know what works for me.   If you are not raising show fish does it really make a difference to you?  Are you heating the fish to 60F for some reason like growth or other factor?  How large are your fish and how big is your system and filter?  All these things can be factors too.

[Stevo]

Thanks for responding, my fish range from 8" to 20" 13 total I have them in a 300 gal rubber maid stock tank with a large bio falls filter I'm turning the pond over 3 time's an hr. I built a new 4000 gal pond this winter and thought it would be better to let the pond seasen threw the winter than putting them in Dec. And for keeping the stock tank warm thru the winter I'm thinking it would be better off to keep the filter bacteria alive than letting it die off at 50*

[Michiponder]

Stevo

Thirteen fish of that size in 300 gal is a very high concentration of koi.  Even with large biofilter it is more dangerous than any concerns about lack of light.  Do you have the capability to do regular partial water changes?  Have you considered raising the salt level to protect against nitrate levels?  At that heavy of a fish load I do not believe I would feed them at all.  Most fish can go for months without eating if thier water quality is good and there is enough O2.  Feeding them would only overload an allready overloaded system.  As far as the filter shutting down from cold I believe that if the water is colder there would be more O2 and the fish would be producing far less waste.  The filter shuts down (not completly) but will stay alive.  One big concern about being colder is that the fishes imune system begins to shut down.  This is risky if the fish are battered, stressed, or infected with even minor concentrations of pathogens.  There are lots of variables to deal with here and lots of different ways to deal with them.  Regular water testing for amonia, nitrite, nitrate, and other parameters might help you get an early jump on heading off any problems.  hope your fish do OK this winter, but please report what happens here so that the rest of us can learn from your experiences.

[Julles]

This is somewhat similar to how people keep herps (reptiles & amphibians).  If your goal is to recreate living conditions, then you would want to heat, feed, and provide light.

But if you want them to more or less hibernate, but in a more controlled environment than your new pond, then you would want cold water, no food, no light - as if trying to recreate a hibernation or estivation state.

[tranquility]

Ditto what Michiponder said...way to many fish in such a small tank....I would diffidently be testing the water and doing water changes(and if you can any way make the water changes the same temp as the water is now thats even better--(I hook my hose up to my shower then I can check the temp in the tank and make sure the water going in is the same temp.) ....If your testing kit shows Nitrites then you'll want to add 2lbs. of salt per 100 gallons(only if your not using any medications--some medications and salt can be deadly)....I buy solar salt at Lowes--alot cheaper than pre-packaged pond salt...
Lawanna

[Kittyzee]

Did you just recently finish your pond before cold weather?  My fish (all goldfish, no koi) live outside 365 days a year.  In winter, it will freeze over and they are in a state of sort of suspended animation.  I know when it warmed up a bit a few weeks ago, I watched my fish grazing on underwater plants, but I won't feed them again until the water reaches about 50 degrees.  I also would be concerned like Michiponder, of high concentrations of ammonia, nitrates, and nitrites. 

I probably would have put them in the outside pond and let them overwinter there.  Keep us posted.   

[Stevo]

Thanks again for all replys. The reason for not putting my koi in the new pond this winter is do to a high ph 10.2 do to the lime in the new concreat I'm waiting for it to leach out thru out the winter and has all ready droped down to 8.1 in the last month an half. And for the indoor pond I agree a few to many fish for a 300 gal holding tank, I am the doing a 60 gal water change weekley and keeping the salt level at 0.10  so far the nitrates and amonuna have been ok. I'am going to back off on the feeding tho to once or twice a week

[tranquility]

when you say ammonia and nitrites have been fine--do you mean your getting a 0 ready? or that they are in exceptable range? I wouldn't dare put fish that have been indoors out during the winter--wait till spring and the water is either the same temp or really close to it...the only thing I would do is to make sure to be getting visuals of the koi at least once a week...making sure no one has any issues trying to arise.....
Lawanna