SLOW METABOLISM:  In wintertime, the fishes’ metabolism slows down. Cellular enzymes which operate in warm water begin to give way to specialized enzymes called :iso-enzymes” which only function in very cold water. In other words, the fish enters an entirely new condition of metabolism, one that is very fragile, and very very slow. Worse, it’s a condition that cannot rapidly be reversed. Rapid warming of fish can be fatal. Short of doing expensive LD50 studies, I relate any twenty-degree jumps or drops in temperature over twenty four hours as being enough to cause clinical illness, or death.

PARASITIC ATTACK:  It has been shown that the number of, and activity of the fishes’ immune fighter cells (B,T and natural-killer cells) are reduced in these very cold conditions. On the other hand, parasites like Flukes (specifically: Dactylogyrus vastator) and Trichondina can ably act as potent pathogens in these frigid waters. So, in many instances the scene is already set for morbidity and mortality in the spring due to the actions of these parasites in cold water without the healing and immune functions of the host fish.

ENVIRONMENTAL NEGLECT:  Also during wintertime, our attention to the pond is often misplaced on other things, like staying warm and getting over the Flu, which was vicious this last winter. Something about going out and ‘leafing’ the pool and backwashing the filter or cleaning the matts doesn’t thrill. So the pond is often in its worst overall condition at this point, and this is the worst time for that to be the case.

INANITION:  In most instances, the fish have not had nutritional support all winter. Snowmen which fall into the pond, and the occasional snow ball are not nutritive, even with yarn lint and dirt mashed into their surfaces. Fish that are not receiving nutrition also experience declining function and number of their immune fighter cells. The lack of vitamin support also has health ramifications.

PROVIDE ENVIRONMENTAL OPTIMIZATION FILTER:  The filter should be backwashed or cleaned out, right now {By March}. Extreme care should be taken to minimize the impact (stress) this has on the fish. Those of you with Bead filters can usually backwash several times and be confident of ZERO organics left in the filter, without subjecting the fish to a big “brown cloud” returning to the pond after the overhaul. Folks with matt and sponge filters can usually clean these very little hazing of the water.  Please realize that “brown clouding” of the water represents a bacterial shower for the fish at a time when they are least able to resist it. It is very stressful and can trigger a negative response; namely, illness. I do not know a way to clean a lava rock or rock-spar filter without getting considerable “after-overhaul hazing” in the water. Good Luck. The rule of the article is that is that the filter should be as clean as possible before the springtime warmup. <CLEAN THE FILTER AND DON’T STRESS THE FISH DOING IT.>

PARASITES:  Amazingly, having some parasites in a natural environment is acceptable. Believe it or not, fish in the wild have parasites all the time and only the weak and old ones die from them. I think one of the reasons the parasites rarely “get the upper hand” is because the parasites and the fish-host have lived together for millennia and they’re spread out over acres of water. In your pond, this is hardly the case. Your pond would typify the most unnatuaral conditions, being relatively* crowded, less sanitary, and simultaneously infested with novel and most diabolical parasitic foes, keenly selected for killing by decades of street fighting with salt, antibiotics and other medications used at the “drop of a hat”. (*relative to Mother Nature’s scheme of things) There are three regimens, which I am fond of for winter to spring preventative health care.

Regimen One:  Get a microscope or borrow someone who has one. You could host a party, promise beer and barbecue, invite some friends but be sure that someone from the MAKC Health Hot Line is on the guest list, then you call them and ask them to bring their microscope. They’ll ask why, and you just say “Oh, I dunno, I was curious what one looked like.” Then when they get there you corner them in a room and tell them they cannot come out until they biopsy three fish in your collection, three times. Have them biopsy: 1)fin, 2)ventral body and 3)gill on three of your slower, more isolated fish. Then kiss their feet and feed (and beer) them well. Drive them home. <IF THERE ARE NO PARASITES, DON’T STRESS THE FISH OR TAX THE ENVIRONMENT WITH A SHOTGUN TREATMENT!!!>

Regimen Two:  Apply salt according to http://www.koivet.com/salt.htm. The “nuts-and-bolts” of this regimen are selecting the correct salt, removing sensitive plants from the pond, and adding your salt in ‘thirds’ over 36 hours. (Specifically: One pound of non iodized, non-YPS, non-mineralized salt per hundred gallons, applied every twelve hours for three treatments; total dose applied will be three pounds per hundred gallons.) Leave the salt in for fourteen days at a minimum but do not leave it in year ’round. Remove the salt with water changes.

Regimen Three:  Potassium permanganate (KmnO4)according to the four-day regimen shown at: http://www.koivet.com/potassium.htm The nuts and bolts of this regimen are that you’ll dose with 4 PPM (one teaspoon level per six hundred US gallons dissolved and dispersed) Potassium permanganate after bypassing your filter to spare your beneficial nitrifying bacteria, leaving the aeration and circulation at maximum levels. When the potassium turns brown or amber as checked in a white coffee cup you’d decolorize and inactivate with one quart of hydrogen peroxide 3% USP per five thousand gallons. Resume filtration. Repeat in 3 days. Repeat again at the eight and twelve day mark to intercept emerging flukes that will have survived treatments one and two. (Very rude note for your own good: You’re just an idiot of you don’t read as much as you can about potassium permanganate before treating with it for the first time. It can be dangerous if misused.)

POND BOTTOM:  Preparation for Spring includes a big component of environmental preparation. The pond bottom should be (certainly by now: February 20^th) clear of ALL organic debris including fish wastes, plant and tree leaves, dead fish, neighborhood cats, squirrels and if any of you find him, Jimmy Hoffa. Again, cleaning the pond out should involve minimal stress would ideally result in NO “BROWN CLOUD”. Every time I write about the formidable ‘brown cloud” I also think about a dog I had as a kid who could clear a room after eating chicken skin we’d feed him under the table - but that’s another story. One way to clean up the pond bottom is to rent what they call a “solids-pump” from your local tool supply - they’re gas powered and made to empty septic systems. (Don’t ask if they sterilize them between uses because they will just laugh at you).

“Solids-pumps” are most unforgiving to small fish but they can take leaves and everything undesirable out of the pond, discharging 100% of the water, so there’s no clouding of the system.

ROCKS AND PLANTS:  Think about the rocks and plants you have in your pond right now, if any of your fish are anywhere near fourteen inches long. These bigger fish will breed, and this involves the males and females rushing into plants and crevices to drop eggs and milt. They get pretty banged up. Make your pond orgy-safe right now. Enough said.

Role of Diet:  As we mentioned earlier, by Spring, the fish have not eaten all winter, and their “immune system” is suffering for it. We conveyed this idea without describing the effects of inanition on the liver’s mitochondrial P-450 oxidase system, failure of glutathione development and the interruption of the cycle of acetyl CoA as it relates to the propagation of cyclic AMP; as you might read in REALLY smart people’s articles..More proof that I am just a hack.

Anyway, the fish have been starving, but feeding heavily in really cold water (<52DF) damages the intestinal lining, which allows harmful bacteria to cross over into the blood stream, resulting in acute or eventual death due to bacterial sepsis.  So we recommend one of two things:

Option One: Feed small quantities, every other day of rapidly digestible feeds without bulk. Such foods would include flake foods like those you give to tropical fish (really, this is what I fed but it’s expensive) Or you can give the simpler and very ideal Cheerios. No milk. Thanks. When temperatures are closer to sixty, you switch to more frequent feedings of regular foods, (Here are some guidelines:

-no corn in the top three ingredients,  -fish proteins in the top tow and -shrimp meal somewhere in the top five)

Option Two: Buy a heater and warm the fish five degrees per day until they hit and hold seventy and feed them ‘til their eyes bulge, while watching Nitrites and abbreviating feeding if surges or derangements in nitrogen reduction are seen.

IMPORTANT:  And with thanks to Betty Roemer for the following “discovery”.

Vitamin C {ascorbic acid} was shown by Dr. Lovell (my hero) at Auburn University to be very good for the immune system. In fact, slight overdoses of Vitamin C increased survival rates of fish under bacterial attack by astronomical percentages.   This has relevance to hobbyists, and forms the basis of the following recommendations. When the fish are eating ‘pretty good’ and seem active, please section a common Florida grapefruit around its equator. Then section these two hemispheres into halves. (Making nice quarters) which float on the surface. My experience is as follows: I found that really, really stupid koi take a  whole ten minutes to find and attack these sections in seventy degree water. My fish found them, to my incredulous amazement, in under seven minutes and ate them ‘til their mouths were pink. Betty and Dick were standing there with me when they showed me the technique and I was amazed by the craze that ensued among my fish. One other thing; watch where the rinds go, they can choke a small pump. Feed the sections every third to fourth day. You will find that if you give a lot of grapefruit every day, the mouths of the koi will become harmlessly but unsettlingly pink. I worried that the ascorbic acid was irritating the mouths so I abbreviated the applications to a twice weekly “treat” format. <GRAPEFRUIT SUPPLEMENTS ASCORBIC ACID AND THIS IS A “GOOD THING”>