By Stephen M. Meyer
Q. Let me start by saying I really love your magazine. It's full of great information from people who really know their topics. I've had saltwater tanks for the past 5+ years and found your magazine to be excellent.
Now for my pond question. I am setting up an outdoor pond with a small trickling waterfall, and wanted to know if it's dangerous to use old wine barrels as part of the this waterfall.
I got the idea from an outdoor landscape company who has a pond set up using three barrels. However, they don't have any fish in the pond. I'm planning on stocking my pond with koi and goldfish and I'm wondering if this would be hazardous to their health. If it is acceptable, do you recommend lining or sealing the barrels before adding water, and, if so, what do you recommend using? Any comments would be greatly appreciated.
A. Worrying about toxicity problems associated with pond building materials is smart. Lots of things can contain water and therefore could be used to create water features, such as falls, streams and pond areas. But many of those things are made of materials, or old substances, that are harmful to sensitive aquatic life — such as fish.
Old wine barrels may contain substantial amounts of alcohol and other substances used in wine or whiskey making. These could leach back into the water and, in strong concentrations, harm your fish. Or they may not.
That said, in principle there is no reason to avoid using these barrels in creating water features. Old whiskey and wine barrels are frequently used for aquatic tub gardens. As mentioned, much depends on the concentration of the original substances in the wood that might leach into the water. Using the barrels as simple tub gardens would produce the highest and most risky situation. But using them as waterfall features for a large pond would probably pose no risk at all.
I suggest you fill the tubs with freshwater and let them stand in full sun. Change the water completely every day for a week. Then refill and put some feeder goldfish in.
Watch the fish for a couple of weeks. Alcohol is used to anesthetize fish, so look for signs of alcohol poisoning, which include listlessness, inability to maintain proper orientation and loss of appetite.
If all seems well, then go ahead and build the falls. If not, go back to soaking and leaving the barrels in the sun again. Allow the pond and waterfall system to run for several weeks before putting in fish.
I realize that all the time inherent in this approach runs counter to the enthusiasm to get the pond going immediately, but it may save you from much bigger hassles later. Patience is your friend when it comes to ponds.
Now, about the mechanics of using the wine barrels. They may be tight enough to hold water reliably, especially after a good soaking. However, there is also a risk that water can seep out through the seams of the barrels, and even small daily losses can drain a pond system quickly.
The waterfall system can be made water tight by using a single-piece liner to both to line and link the barrels in one continuous form. Rocks placed on the liner segments, covering the bottoms of the barrels, will help strengthen the integrity of the falls, aerate the falling water, create natural water sounds and add habitat for bottom-dwelling aquatic invertebrates. Stone, dirt and plants can be set around the barrels and liner to give a natural appearance.
Pond Kits
Q. I've noticed that some home centers are selling pond kits — kind of like the aquarium starter kits in pet stores. Are these a good way to get started in the pond hobby, or do these kits suffer the same problems that aquarium starter kits do — marginal quality items that won't really do the job? I don't have a lot of money, or space, for a pond, but I'd like to have some kind of a water feature in my garden.
A. Ten years ago pond starter kits were virtually impossible to find locally. Neither aquarium stores nor garden centers kept them on their shelves. Only specialty mail-order firms offered them.
Things have changed. Now you can walk into most garden centers and select from several starter kits — everything from simple tub water gardens to 1000-gallon ponds with waterfalls.
I think these are a great way to get your feet wet in pondkeeping. These kits offer fish-safe liners, pumps, instruction manuals and other "extras". All you need to do is dig the hole.
Of course, "kits" of any kind suffer from the problem that they are designed to appeal to the average buyer and may include what serious pond hobbyists would consider "marginal" products. But remember these are starter kits. One of the goals is to keep the cost down so buyers will take the plunge into pondkeeping without getting soaked for lots of money.
In my experience, first ponds rarely last long, even when it is a custom pond designed and built from carefully selected components. As one's experience in pondkeeping grows, so does the desire to improve the pond. Would you really want a pond kit with a liner guaranteed for 20 years? No.
Select the pond kit that matches your space and your budget, and think of it as an experiment. Play with the design. Learn by doing. Later, should you decide to rebuild a more elaborate pond, you can always reuse the components from the kit. For example, the old liner could be used to make a pool at the head of a waterfall, or to sculpt the waterfall itself.
Fish on the Farm
Q. I'm a city person (although my town is rather small as cities go), and have been amused to listen to the janitor at work telling me about her goldfish all summer. It seems that farmers here have goldfish in their stock tanks to keep the algae down and keep the tanks clean. With the water heaters they have in the tanks for the winter the fish do all right without any extra care.
I don't know how the fish feel about the cattle and other animals drinking the water they are living in. Nevertheless she's been telling me about the baby goldfish that have appeared, so evidently the fish are happy.
Obviously, the fish will be fine in such a tank. But I had never before heard of this practice and wanted to add to the discussion. Any thoughts?
A. Sue, your story is not really hard to believe. In fact, it shows just how hardy goldfish really are under the "right" conditions.
Why do aquarists seem to have so many problems keeping goldfish alive and thriving in small (20 gallon) tanks? Why do pondkeepers have substantially fewer problems with goldfish, but more significant problems with koi? The riddle is answered by your story.
These cattle troughs routinely hold between 150 and 300 gallons of water. Several goldfish are placed in them, and they are never fed. Instead, the goldfish live off of algae growing on the trough walls and insects that fall into the water. They also cannibalize each other and eat their own eggs.
Underfed and under-populated, they produce little ammonia. What ammonia they do produce is detoxified easily by nitrifying bacteria that populate the tank walls. These cattle troughs reach a comfortable and sustainable biological equilibrium.
So, the secret of success here is fish load control and feeding management. A low fish mass-to-water volume ratio and low levels of feeding produce healthy and stable fish populations in these cattle troughs. Six goldfish in 300 gallons is equivalent to one goldfish in a 55-gallon aquarium. Now, who do you know who stocks a goldfish tank like that?
Over the years I've received numerous letters from readers taking me to task for unrealistic recommendations for stocking goldfish tanks. In most cases these people simply don't understand that goldfish are massive fish for their length, that they need water high in dissolved oxygen, and that they produce significant amounts of waste, making modest stocking densities essential if good water quality is going to be maintained in an aquarium.
I typically suggest that a pair of goldfish in a 30-gallon tank is already a little crowded, and that a 55-gallon tank would be even better. Not many goldfish keepers are willing to accept such a recommendation. Most hobbyists also overfeed their fish, adding to the bioload in the tank. The filtration system cannot cope with this, and the water quality deteriorates to the point where the fish are under chronic physical stress and become sick.