Fall Feeding

[Gordo33]

After rebuilding my pond and adding koi I started feeding the fish for the first time this summer. Prior I only had goldfish and they thrived on what was available in the pond. So now I am trying to figure out how to feed as the air and water Temps decline.

I have read and reread threads here and on other sites about how to proceed with feeding goldfish and koi as the fall weather decreases the ponds water temperature. Like many other hot button topics associated with this hobby there seems to be varying opinions.
Based on what I have read I have come to the conclusion not to change what I feed but rather the amount. There doesn't appear to be scientific evidence to support gut rot in koi from feeding high protein foods when the water temp cools down. What I have read leads me to believe the issue is the the decrease in BB population with decreasing temperatures which will cause ammonia to build up in the water.

The perfect weather scenario, which doesn't exist where I live, has temp decline causing both a slow down in fish activity/metabolism and a decline in BB bacteria . Perfect harmony less ammonia produced as critters available to break it down decline.

But what happens when the weather becomes uncharacteristically warm even if just briefly and the fish become more active looking for more food.
If I feed more they will produce more ammonia. Then the weather abruptly turns cold again lowering the water temp below 50 so now there is significantly less BB. Then the temperature rebounds again fish are more active looking for food so I up the feeding again . This has been the weather cycle here the past few weeks . We had an overnight close to freezing followed by Temps in the 60s, back down again and last week in the 70s. This week the air Temps have been in the low to mid 50's and the water temp in the upper 40s to low 50s. I have been lightly feeding once a day approximately 25% the amount of normal feeding. Tonight the air temp is going down to the mid 30s and Saturdays low is going to be in the 20s. I dont plan on feeding the next few days.. I would think those Temps will wipe out the majority of the BB.

My question with this scenario is what do do about feeding when next week's Temps increase back to normal ,around mid 50s , and the fish start looking for more food. Will the BB rebound to higher numbers if I lightly feed again or will I be creating an ammonia spike?

 

[Gemma]

I switched to Wheat Germs last month, and I'm done feeding for this year! Once I stop feeding because it's too cold, I don't start up again just because it gets a little warmer,I will resume feeding in Spring

 

[teeemkay]

I stopped feeding the fish about 2 weeks ago. Once we get a good cold snap, they lose interest in the food really quickly. It's always right around mid- to late October. Even if the weather warms back up, I don't start feeding them again. If they get really hungry, they nibble on the algae around the edges of the pond.

 

[audioenvy]

It sounds like you know this but generally speaking it's not the air temperature but the water temperature that you'll want to watch. Unless your pond is quite shallow its temps will swing much less wildly than air temperatures. That said, it won't hurt the koi to go without food for a while or to have less food even when the water is relatively warm.

Your mileage may vary but my own plan is to only feed every few days once the water gets to 45-50 degrees and then from 40-45 (hopefully I won't get that low with the cover on!) maybe only once a week but removing any uneaten food. I personally am trying to prevent the fish from just sitting on the bottom in full torpor for three months. That's what I did last year and no fish died and I know lots of people do that without issues but since I've gone to the trouble of putting on a winter cover if I can keep the water 45+ degrees I'll feed sporadically all winter.

 

[RichardSJPonds]

In water below 50°F their digestion slows down so much that the food they eat can sit there and rot in their bellies. That info comes from the KoiVet, he has autopsied fish that didn't make it thru winter and discovered this is whats happening.

http://www.landvistaaquascapes.com/blog/how-much-should-i-be-feeding-my-koi

 

[Meyer Jordan]

After rebuilding my pond and adding koi I started feeding the fish for the first time this summer. Prior I only had goldfish and they thrived on what was available in the pond. So now I am trying to figure out how to feed as the air and water Temps decline.

I have read and reread threads here and on other sites about how to proceed with feeding goldfish and koi as the fall weather decreases the ponds water temperature. Like many other hot button topics associated with this hobby there seems to be varying opinions.
Based on what I have read I have come to the conclusion not to change what I feed but rather the amount. There doesn't appear to be scientific evidence to support gut rot in koi from feeding high protein foods when the water temp cools down. What I have read leads me to believe the issue is the the decrease in BB population with decreasing temperatures which will cause ammonia to build up in the water.

The perfect weather scenario, which doesn't exist where I live, has temp decline causing both a slow down in fish activity/metabolism and a decline in BB bacteria . Perfect harmony less ammonia produced as critters available to break it down decline.

But what happens when the weather becomes uncharacteristically warm even if just briefly and the fish become more active looking for more food.
If I feed more they will produce more ammonia. Then the weather abruptly turns cold again lowering the water temp below 50 so now there is significantly less BB. Then the temperature rebounds again fish are more active looking for food so I up the feeding again . This has been the weather cycle here the past few weeks . We had an overnight close to freezing followed by Temps in the 60s, back down again and last week in the 70s. This week the air Temps have been in the low to mid 50's and the water temp in the upper 40s to low 50s. I have been lightly feeding once a day approximately 25% the amount of normal feeding. Tonight the air temp is going down to the mid 30s and Saturdays low is going to be in the 20s. I dont plan on feeding the next few days.. I would think those Temps will wipe out the majority of the BB.

My question with this scenario is what do do about feeding when next week's Temps increase back to normal ,around mid 50s , and the fish start looking for more food. Will the BB rebound to higher numbers if I lightly feed again or will I be creating an ammonia spike?

What an excellently framed question.
First, let's re-establish a couple of facts (not opinions)--
--Nitrifying bacteria/archaea remain alive until water temperatures reach 0C/32F or lower. Like any other organism, reduced temperature will reduce the activity of these bacteria. Although they cease growth they remain alive and viable.
--It has been established by several scientific studies that Koi (and Goldfish) continue to feed (and produce Ammonia) as water temperatures drop. Because lower temperatures slow their metabolic rate, the demand for food is curtailed but not eliminated.

The change of season is never a smooth gradual transition of temperature levels, but rather a series of cooling and warming until the next season's temperature level range is reached. In Nature, this does not cause any issues as all aquatic organisms change somewhat simultaneously in response to temperature fluctuations. For example, as temperatures drop, fish require less nutrient intake which results in less Ammonia production. At the same time the activity of Nitrifying bacteria/archaea is being reduced but not so fast as to not be able to oxidize the Ammonia/Nitrite produced.
Bottom line is that the activity of aquatic organisms is based on the current water temperature not any historical levels even a few hours preceding.
Feed the fish as you normally would, but only what they can consume in about 5 minutes, removing any uneaten food.
You are indeed correct in stating that there is no scientific basis for the claim that food rots in a fish's digestive tract. No disrespect for Doc Johnson. If this were so, fish mortality would be common place in natural settings every time the seasons change and this is certainly not the case.

 

[Lisak1]

I would guess the same would be true of most human autopsies - you're going to find food in the gut, unless the person was on a starvation diet or had stopped eating due to some other medical issues. Assuming that the finding of food in the gut (even if it is rotting - because that's basically what food DOES in your gut) is what caused the death is making a giant leap in what is most likely the wrong direction.

 

[Jimmy Gibson]

I have not fed my Koi in over two weeks, the water temperature this morning was 52..... so this afternoon I backwashed my filter, so when I was replacing the water, got it a little higher to a dried up algae line, looked out a few minutes ago and they were all lined up munching on that algae..... even though they are moving like they are in slow motion they are still taking advantage of what’s there to eat.....mine won’t get any more food from me until spring and the water temperature is consistently above 60

 

[Faebinder]

I have not fed my Koi in over two weeks, the water temperature this morning was 52..... so this afternoon I backwashed my filter, so when I was replacing the water, got it a little higher to a dried up algae line, looked out a few minutes ago and they were all lined up munching on that algae..... even though they are moving like they are in slow motion they are still taking advantage of what’s there to eat.....mine won’t get any more food from me until spring and the water temperature is consistently above 60

I stopped a week ago myself.

 

[addy1]

My pond is now 41F! The temp has dived down with this cold snap.

 

[audioenvy]

My pond is now 41F! The temp has dived down with this cold snap.

Wow, that was quick! My garden hose is frozen solid in the morning but my pond water temps are still hovering around 60 degrees.

 

[addy1]

I didn't get the bog shut off as soon as I usually do, any cold nights drives the temperature way down. The pond was in the high 40's when we shut it off. Too much surface of moving water, cools it right down.

 

[Faebinder]

Same here with the cold snap... even got one of my fish sick... I shut off the bog too.... last year I had it going till it hit the 20s. A few days after I shut it down my irises and the rest wilted nicely. We'll see what makes it this year.

 

[addy1]

I need to groom the bog now, might wait until spring, but with this cold snap most of the plants died. Or just wait until spring.......... In the spring I yank a lot of the plants out as they start to grow.

 

[Faebinder]

Considering how much you guys scare me of irises, I'm debating pull them out in spring, splitting them in half and tossing out half of them.