That Fish Blog – Aquarium Advice and Information

Hello, Frank Indiviglio here. As fall arrives in the temperate zone, outdoor koi ponds will need some attention if all is to go well when the temperatures drop.

Basic Considerations

The metabolisms of both koi and the various bacteria that occupy the pond and filter slow down as temperatures fall. Your fish will not be as hungry as usual, and leftover food will not decompose as quickly as in the summer. Dead plants and other organic material in the pond may also remain more or less “intact” through fall and winter.

However, don’t be fooled by the relative “quietness” of this time….as temperatures rise in the spring, decomposition will begin and the resultant ammonia spike may kill your fishes. Therefore, take care to be extra vigilant in removing organic detritus from your pond as fall approaches.

Cleaning

Be sure that your pond filter is in good shape and running well…rinse or replace filter media and continue with routine backwashes.

If necessary, install a leaf cover or net. This is not merely an aesthetic consideration…decomposing leaves will rob water of oxygen, lower the pH and increase the ammonia level.

To control the amount of dead plant material that enters the pond, remove any aquatic or emergent plants that will not survive the winter.

Health Checks

It is especially important that your koi be in good health as the weather changes. Immune systems will be stressed by the falling temperatures, leaving the fishes open to illness and parasitic infection. Bacteria and fungi that are ever present, and may be of little concern to healthy fishes, will prove dangerous to those not in the peak of condition during the fall and winter.

Feeding

As fall progresses, switch your koi from high protein pellets to more easily digested foods or wheat germ based pellets designed for use in cool water. Do not feed your fishes when temperatures drop below 52 F.

Temperature

Make sure that heaters or surface de-icers, if required, are in good working order. If you utilize a heater, set its thermostat for 62 F. Koi will feed lightly at this temperature, but keep an eye out for leftovers. In unheated ponds, cease feeding at 51 F.

Further Reading

For optimistic readers already thinking spring’s arrival, please see our article Koi, a Matter of Extremes in Spring.

Please check out our koi and outdoor pond books for further information.

For interesting forum comments and photos dealing with overwintering koi under extreme weather conditions, please see the forum at koi-bito.com.

Please write in with your questions and comments.

Thanks, until next time,

Frank Indiviglio

Japanese water garden image referenced from wikipedia and originally posted by Solipsist

It’s starting to get warm. Really warm in the U.S. And, for many of you, you’re starting to notice your pond plants are starting to kick it into overdrive.

Pond Plants, more than most other plants in my opinion (probably because they always have access to water) can really kick into growth once the water temperature goes up. I’ve been one of the folks who literally starts throwing  away the water hyacinths I paid 4 bucks for a few months earlier because I have no where to go with them. I’ve seen the dwarf moneywort in my pond run out of room within and establish itself OUTSIDE the pond. Even hardy pond lillies, while beautiful, can go to town in a mud bottomed pond.   

It is these rapidly growing plants which form some of the most environmentally invasive species available. Imagine, what’s happening in your pond allowed to carry on unabated in a large lake? Unless you can properly dispose or trade them, do not introduce them back into the wild. The threat of serious ecological impact is particularly strong from these seemingly unstoppable plants.

Many local garden clubs or websites will be happy to share and swap out plants with you. You may even be able to pick up a new species or 2 for your water garden. As in all things, consider the impact before you act…..

For more information on invasive plant species within the US, check out invasivespeciesinfo.gov.

Patty here.

It’s inevitable. Just when you think your pond is looking its best and all is right with the world, they invade. Aphids, weevils, moths, beetles and others descend onto those beautiful lilies, floaters, and marginals like a summertime scourge.

So what are some solutions to these nasty little pests? Being that your pond is most likely home to other inhabitants like koi, goldfish, frogs and other desirables, you’ll have to consider safe treatments, and the factor will rule out most chemical solutions.

Aphids are one of the most common invaders, sucking the life out of lilies, water lettuce and other soft-leaved aquatic plants. To avoid or minimize their foothold, prevention is the first step. Remove yellowing or damaged leaves from plants, they serve as beacons for the little suckers to home in on. Resist the urge to blast them off of leaves with a hose, as it usually serves more as high speed transport to other plants than as an eradication method. If only a few are present, you may be able to dunk the leaves or pull out putted plants and spray them away from the pond, at least as a temporary fix.
For more serious infestations there are some other methods to consider. You can try natural predator introduction. Ladybugs and green lacewings are natural aphid predators and though you may have a couple of these arrive on their own, you can purchase them online or at many garden centers and introduce them to feast on your pests. Orfes, minnows and guppies may also eat those that you can rinse into the pond. There are increasingly available herbal sprays for pond plants that will not harm fish, but be sure to read labels carefully. These sprays are usually formulated with herbal extracts, so they’re natural and mild, but sometimes too mild to really handle the situation. If you have the means you may even be able to formulate a similar spray by making a strong tea of rosemary, garlic, thyme, chrysanthemum or mint. Some suggest adding a cup of vegetable oil or a dash of dish soap to the mixture as well, but especially in the case of the soap, be sure to spray and rinse the plants well outside of the pond.

Other common pests include mosquitos, Leaf miners, and aquatic moth larvae. Prevention of infestation of these pests consists mainly of good maintenance of the pond and surrounding area, good water movement and the absence of dead leaves and debris in and around the pond. The natural predators mentioned above as well as others like predator wasps and dragonflies that are drawn to flowering plants and water may help, as may the small insect-eating fish mentioned above. Mosquito dunks are effective for the control of many waterborne insects, but they will also affect beneficial water insect larvae, so if you like those dragonflies, they may not be the best option. They are safe for use with fish.
Even though these pests can create a real headache for those of us with a love for aquatic plants, the overall aesthetic and health of a well- planted pond is worth the hassle. If you have any questions about a pest plaguing your water feature or you have a remedy that has worked for you to share, please let us know!

Image referenced from MorgueFile here.

Patty here. Just about anyone with an ornamental pond has either heard of water hyacinth or has a personal experience with hyacinth to share.  I find it to be an interesting and useful plant, and here in PA we don’t have to worry about its invasive tendencies and notorious reputation like those of you in warmer climates.  I thought I’d give a little background on this floater to help you get to know it better.

Water Hyacinth (Eichhornia crassipes) is native to tropical South America where it forms vast mats on the water’s surface.  It is sun and heat loving and can reproduce at a ridiculous rate by producing long runners and stolons, which is why it is cosidered a noxious and invasive species in many states and countries.  They can double in population within about two weeks if the conditions are right!

It has unique structure.  Each leaf has a spongy bulb which allows it to float on the surface, and the leaves have a waxy, waterproof feel.  The root system hangs in a long-stranded cluster beneath each plant, and the roots are white to dark purple-brown and very hairy.  These plants also produce beautiful flowers in the peak of summer, a cluster of light purple flowers with six petals each and a violet and yellow accent on the top petal of each flower.

Hyacinth does have its notorious side, and the reputation is well-deserved.  However, in cooler climates, and with responsible management this plant has carved out a valuable niche.  Because hyacinth grows and reproduces so rapidly, it makes a terrific solution to provide shade on ornamental ponds.  Two to three single plants is usually way more than enough to cover a broad area of water surface within a few short weeks, ad it will be necessary to prune the mat to keep the population in check.  The floating mat is a refuge for pond fish and frogs, a food source, and a form of natural, efficient biological filtration. 

The foliage and blossoms are as pretty as they are useful, but the roots are the real prize.  Not only do they provide a surface for fish to deposit eggs, but they serve as a safe haven for fry, tadpoles, and other organisms as they grow.   They have the ability to remove toxins, excess nutrients, and other compounds from the water and have even been used in industrial water treatment applications.  Hyacinth helps to oxygenate, and can even be placed in the filter’s sump as long as there is enough sun!

Hyacinth can be purchased for use in garden ponds in most aquatic garden and pond centers.  We sell it out of our retail location, but do not ship it. It is actually prohibited in many southern states.  If you choose to introduce hyacinth to your pond, don’t overdo it, purchase 2-3 plants, and see how they grow!  Provide them with plenty of sun, and protect the plants from your fish (who will think they are delicious) until they start to reproduce.  And as always, be careful and responsible if you need to dispose of extra hyacinth to ensure that they don’t find their way into natural ponds and waterways.

Anyone who keeps a koi pond in cooler temperatures has been there. You start getting a few warmer days in late March and your koi, who had been inactive all winter, begin to swim around and look for food. Being the “good” koi keeper you are, and just an all around nice person, you start feeding your hungry friends almost immediately. The feeding continues to increase, while your pond continues to get greener. Meanwhile the local garden store is getting in a load of excellent looking Asagi or Shiro Utsuri Koi direct from Japan next week, and though you already have a questionable number of little Koi in your 1000 gallon pond, one more couldn’t hurt, right?

Pond keepers are creatures of extremes and it’s nothing we’re ready to apologize for (I mean, koi are soooo cool!). But, from a biological balance perspective, it’s really easy to start tipping the scale in your pond in favor of algae and unfavorable health conditions, particularly in the cooler weather.  

Believe it or not, koi in an outdoor pond do not have to be fed to survive. Being the scavengers that they are, they’ll have no trouble finding the nutrients they need among the detritus, bugs, and general wild things that end up in your pond throughout the season. What this means to you is everything you add to the pond, whether it be more fish, fish food or plants, adds to the nutrient load. In early spring, this nutrient load is particularly important for several reasons. First, your beneficial bacteria are not yet running full steam. This means ammonia takes that much longer to break down. When you combine that with the fact that your fish, and their immune systems, are still in slow motion due to the cooler water temperatures, a high nutrient load can cause problems. In addition, the natural “nutrient sucker-uppers,” your aquatic plants, are also struggling to gain a hold for the new season, so that part of your natural filtration is crippled as well.

Many koi keepers than ask, how can I get around this problem? I love my pond and I’m not going to stop feeding my koi, and I’ll probably add more fish to the nutrient load from time to time because they’re too awesome to pass up. Our response to you: avoid the extremes. Be sure to have the necessary test kits on hand to make sure levels remain nominal throughout the season. If you start to see problems, just like in an aquarium, try a water change, or add some bottled bacteria to help the chemistry settle. If your pond starts to get cloudy or full of algae, try adding more plants, or cutting back a few feedings. If you’ve tried all of these solutions and the problems are not going away, it may be time to consider a larger filter system or (gasp!) trimming your koi stock a little.

Good luck with your pond this season!