Ponds and Water Gardens
Assassin Snails – Killer Snails for Your Aquarium
Dec 21st
In my first blog, I talked about why the Zebra Loach (Botia striata) is well suited for smaller aquariums, and why it was certainly a more sensible choice for snail control than its larger cousin, the Clown Loach. The Zebra Loach is one of the most under rated of the snail eating Botia, in my opinion. But what if you have a planted aquarium and you’re keeping small shrimp? Zebra Loaches may very well eat them! Or what if you have a small tank, but don’t have room to house 4 or 5 of these fish? Well, I think there may be something that is just as effective, does not appear to want to eat the little shrimp, and won’t take up a lot of room. A somewhat new introduction into the hobby called the Assassin Snail.
The Assassin Snail (Clea helena or Clea Anentome helena) comes from lakes and ponds in Southeast Asia, where it feeds on decaying protein, worms, and other snails. That’s right, a snail that eats other snails. Voracious little predators, the Assassin Snail has an attractive yellow shell with a spiraling brown stripe wrapped around it. While they do have an appetite for snails, predation does not occur within their own species. This allows several individuals can be kept in a single small aquarium. At an adult length of just under an inch, a 10 gallon aquarium could easily house a dozen of these snails. They are pretty durable and can take a wide range of water chemistry, as long as it does not fluctuate greatly. While preferring a pH of 7.0 or 7.2, they can tolerate a range from slightly above 6 to about 8.2. Water hardness, can also be somewhat flexible. Reports of keeping them in water with GH values of 5 and a dKH of 1 seem to be pretty standard. Fine gravel or sand is always preferred, but not a necessity. If you do have fine substrate, these little guys will burrow and crawl through the substrate in search of food.
Assassin Snails are known to be extremely active. The idea that snails are slow and plodding is definitely challenged by this gastropod. Assassin snails will scale plants, glass, large stones, and wood with surprising speed when hunting for food. I have even seen them suspended upside down on the surface of very still water! Being able to move quickly gives this snail an advantage over slower moving prey items, such as the troublesome pond snail, Physa sp. In large numbers, Physa sp. pond snails can damage soft plant tissue and can present a real problem if you are trying to keep a well-groomed planted aquarium. A handful of Assassin Snails will eventually clear the aquarium of unwanted snails. After the problem snails are eaten, Assassin Snails will take up a somewhat more laid back role by eating left-over fish foods and decaying protein. While some reports of shrimp predation have occurred, it is a pretty rare occurrence.
Watching a group of these curious little snails cruising around your aquarium is really fascinating. I have never really gotten absorbed into the snail world, but seeing the Assassin Snail hunt and forage for food has definitely piqued my interest! From my personal observations, I have to say that these snails are definitely more than capable of ridding an aquarium of unwanted snails. They may be the predator you’ve been looking for.
Thanks, until next time,
Craig
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Loading ...Koi Ponds in Autumn – Maintenance and Dietary Changes
Sep 23rd
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
(No Ratings Yet) Loading ...Overgrowing Pond Plants and Invasive Species
Jun 24th
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.
(No Ratings Yet) Loading ...Dealing with Pond Plant Pests
Jun 12th
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.
(No Ratings Yet) Loading ...Anchor Worms: a Common Springtime Pest in Koi and Goldfish Ponds
May 18th
Hello, Frank Indiviglio here.
Anchor worms are crustaceans (specifically copepods) and as such are more closely related to shrimp than to worms. They often make their presence known in outdoor ponds as winter turns to spring. Lernaea elegans, the most commonly encountered species, remains dormant during the winter and becomes active as the water reaches 55 F or so.
Identification
Anchor worms bury below their host’s scales, but betray their presence by trailing ¼ to ½ inch-long portions of their black, thread-like bodies from infected fishes. They usually attach about a fish’s gills, eyes or fins, but can occur most anywhere. Other signs include inflamed or raised scales and efforts by fishes to dislodge the parasites (leaping, rubbing).
Infestations most commonly occur during the spring, when the parasites are searching for new hosts after their winter dormancy. Conveniently for the anchor worms, the immune systems of pond fishes are at their weakest at this time, having been stressed by cool temperatures and the long winter fast.
Secondary Bacterial Infections
Anchor worms rarely cause fatalities, but the wounds they inflict frequently become infected by opportunistic Pseudomonas and Aeromonas bacteria. Ever present in the pond, these pathogens can easily kill fishes, especially those with depressed immune systems.
Avoiding Anchor Worms
Be especially careful to check for anchor worms when purchasing koi or goldfishes in the late winter or spring…those that have been wintered outdoors may be infected. They also parasitize weather fishes, channel catfishes, hi-fin loaches and other species commonly kept in outdoor ponds.
Anchor worms of various species can also be introduced to your collection via tropical fishes which have been raised outdoors.
Treating Parasitized Fishes
Fortunately, Jungle Lab’s Anchors Away is an effective treatment for infestations of anchor worms and certain other parasites. Be aware that this medication will kill crayfishes, snails and other invertebrates, and that carbon should be removed from your filter while treatment is ongoing.
It is also useful to add an ultraviolet sterilizer to your pond’s filtration system. UV sterilizers will kill anchor worms in the free swimming larval stage (they are not effective against adults), thereby preventing re-infestation.
Further Reading
A detailed article (Food and Agriculture Association of the United Nations) on the life cycle of anchor worms and related parasitic copepods is posted at.
Please write in with your questions and comments. Thanks, until next time, Frank Indiviglio.
Image referenced from Wikipedia and originally posted by Brian Gratwicke
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