Part 8 of 8: Choosing and Caring for Fish

You’ve completed your pond, treated the water and let it settle in for a few days. You’ve installed your aquatic plants and your waterfall is splashing soothingly. Now, if your plan includes fish, selecting the right ones is an important step in completing your pond or water garden. If maintained in a healthy environment large goldfish and koi will live for many many years, providing hours of enjoyment. More importantly, studies have shown that simply watching fish relieves stress and reduces your blood pressure.

Conditions in your area of the country and the design of your pond will determine if you will be able to keep fish. If you live in a cold climate, there should be one area of the water garden deep enough to provide a safe haven for your fish when the top of the pond freezes over. In contrast, if you live in a hot area of the country, a shallow pond may heat to high levels where fish cannot survive without your constant supervision or care. We suggest talking to your fish dealer or consulting other water gardeners in your area before deciding to add fish to a water garden. Hardy fish can adjust to a range of temperature, but a sudden shock to cold water may harm the m. Small fish have little chance of surviving a drop of more than 15 degrees. Wait until water temperatures warm into the low 60s before adding fish from indoor tanks to outside ponds.

Before adding fish take steps to help them survive and prosper. Allow your freshly-filled pond to stand for 24 hours to settle. Add a solution such as Tetra Pond Aqua Safe to tap water to remove chlorine compounds. If you have used concrete in your pond, take a reading to find out the pH of the water. A pH reading of 8.5 most likely contains dissolved concrete, too alkaline for fish to survive. A pH reading between 6.5 and 8.4 is needed to sustain healthy fish.

Add fish to the pond gradually over a period of several months. Go slowly. To begin, we suggest adding just a few fish; maybe 12 small goldfish to test the water. Remember your fish will grow fast and reproduce. Adding three or four fish every week will allow the pond filter to cope with the increased quantities of fish waste and ensure the water quality remains good.

Choose Fish Carefully

Care should be taken when choosing fish. This step is somewhat like choosing a diamond: the most important elements are size, quality and color. Pond fish, especially Koi, can be expensive. It’s important to find an honest, knowledgeable dealer who will help you select the right fish for your particular pond. Once you’ve chosen your fish, you must get them home, get them acclimated to your pond and hope they didn't bring any infectious friends with them.

When shopping around for a pond fish supplier, look for a clean, well laid out establishment with friendly, helpful staff. A good dealer will purchase fish from a hatchery, not a re-wholesaler or warehouse. Hatchery-direct fish are cleaner, less stressed, and healthier. The dealer should also quarantine new fish shipments for at least two weeks.

The dealer should have a good reputation and a thorough knowledge of pond fish keeping. His holding tanks should be well aerated, well filtered and not overstocked. They should be clean and free of floaters, salted properly and should never smell abnormally fishy. Inquire about water conditions and ask the clerks what they feed their fish. But don't expect long personal service during the busiest times of the day.

The dealer should also be well-versed in the potential problems associated with the hobby such as proper diagnosis and treatment of diseases. He should also stock a supply of pond related medications. A good supplier will add a conditioner to the bag to help reduce stress to the fish.

Spend time looking at your intended purchase. Look for erect fins on alert, active specimens. Never buy lethargic or hyperactive fish with drooping fins. Fish should have a good appetite and be willing to eat. Look for bright, but not overly dark or faded, colors. Unusual coloration often indicates stress. The fish you choose should be well rounded and filled out with no concave areas on their bodies. Avoid abnormally bloated fish. Check fish carefully for sores, redness or swellings, abnormal patches of skin, growths or other suspicious marks. If you see any, don't buy the fish.

Try to keep your eye on a particular fish for a short time before having it netted out. Once the fish is in the bag, inspect it even more carefully. Check for shiny eyes, missing scales or strange marks on the body.

The size of your pond will dictate how many and what types of fish you can keep. Ponds of 1,000 gallons or less should be stocked with smaller species such as shubunkin, goldfish or golden orfe. Koi need lots of room, so your pond some be larger than 1,000 gallons. If you plan to keep many koi, your approach to pond keeping may have to be different. The number of fish you add will directly relate to the amount of work needed for your pond!

Fish are graded according to size. All small koi, even the select ones, look the same when they are small. When choosing koi, remember they are meant to be looked at from above. Look for fish that have proper conformation -- a torpedo-shaped body that glides through the water. The head should be rounded with the eyes proportionally set apart. A fat fish can be the sign of poor nutrition or health. The fins should be erect and fan-like, not torn, bent or closed. And don't disregard the long-finned or butterfly koi that are becoming popular.

Solid black, platinum and multi tones are just a few of the colors available. Solids should be rich and glowing. The different colors must be separated with no faded sides or washed-together look. Remember, fish lose their color when frightened.

Getting Your Catch Home

To keep your new fish alive and happy, take them home immediately. The less time they spend in a bag the better off they will be. Never leave your newly-purchased fish in a car on a hot sunny day unless you like them par-boiled or poached. If at all possible use a cooler to transport the bagged fish home. This helps keep the temperature stable and the fish happy. Keep fish in the dark on the way home if possible. They're a lot calmer being transported this way and are less likely to flip around and get stressed. As much as we like fish, they're not too bright; lights out and they think its time to go to sleep.

Adding Fish to the Pond

Fish are usually bagged in plastic bags with air trapped at the top. Before you release the fish, float the bag for about 15 minutes to allow the temperature to stabilize. When you open the bag, cuff the sides; let it float about 15 minutes and add one cup of pond water. Repeat this procedure three or four times. The entire process should take an hour or more. Release the fish by netting it out of the bag and dispose of the water in the bag outside of the pond. Your new fish will dive to the bottom, but will return soon enough to the top.

For established ponds, quarantining is recommended. This means providing a place separate from your pond where you can observe and treat, if necessary, new or sick fish. A livestock tank or bathtub full of water plants placed in a cozy corner of the garden works well. This may sound excessive or unnecessary, but you will thank yourself for doing it if your fish are important or expensive. This is also another good excuse to add one more water feature to your landscape.

Do Not Overstock Your Pond

Overstocking causes the majority of fish diseases, death and algae problems in the typical water garden. Proper stocking begins with knowing how large your fish will be as adults and using this information when figuring how many fish you can keep. Keep in mind that your average koi will grow to 36 inches long and weigh about 20 pounds.

The rule of thumb that you can have one inch of fish per gallon of water does not really work in a water garden, especially with koi. You may also have heard that "fish will grow only to the size of their container.” This may true of some of the smaller tropical species, but not with koi.

While it might seem excessive, 36-inch long adult koi will need around 400 gallons of water per fish to maintain a balanced pond. A shubunkin or goldfish will require considerably less, around 50 gallons per fish. The two fish can co-exist if needed, but are best kept separate. Shubunkin as a rule are much more peacefully inclined towards planted ponds than are koi.

Strictly speaking koi ponds have somewhat different rules than do garden ponds. You may have to decide which is best for you. If you wish to have plants, use the above stocking rules and stick to shubunkin, goldfish, or golden orfe. You might add a few koi, but be careful … they will eat your aquatic plants.

Feeding Your Fish

Simply put, fish are too dumb to know when they are full of food. They are genetically programmed to look for bits of food all day. Feed your fish sparingly, but often, using a high quality food formulated for the type of fish you are keeping. Fish do not digest large amounts of food well, therefore feed only what can be consumed in about three to five minutes or less. For koi, choose good staple food labeled for koi, supplemented with fresh veggies and seafood if you really are into spoiling your fish. See our fish food section for more information.

Never feed your fish if the water temperature is below 50 degrees, Fish are cold-blooded creatures, so their metabolism is tied to the current temperature. If you feed below 50 degrees the food literally rots in the fish's belly creating what can be a fatal condition for your pet. If you have a lightly stocked medium or large pond, you may not need to feed your fish at all. Let nature take its course. If you are more heavily stocked, your fish can go for three to five days without being feed with no ill effects.

Caring for Pool Fish

In most areas of the country with a pond built deep enough, koi and goldfish can be left in the pond year-round. During the summer they are very active and eat often. If you have more than just a handful of fish, you will want to supplement their natural food of leaves, algae and insects. You can feed frequently, every day feedings help tame your fish. As a general rule, feed no more than what can be consumed in 5 minutes.

As fall approaches and water cools, the metabolism of the fish slows. When the water temperature reaches 45 degrees, your fish will stop eating and go to rest at the bottom of the pond, waiting until the water warms again in the spring. Never do a super cleaning of the pond. In the fall remove old leaves and silt from the pond bottom by running a net along the bottom. In the spring, when the fish start to swim and the water warms, skim the net along the bottom of the pool to remove debris. You may use a sump pump to remove silt and up to 50% of the pond’s water. Remember, the fish feed on algae in the pool. Be sure to add water conditioner when adding more than five percent of the water’s volume. Refer to our seasonal pond care articles for more information on this subject.

As long as ice doesn’t cover the pond for weeks at a time, fish can survive the winter. Placing a water pump just under the water’s surface can keep the water open all winter. In a pinch, set a pot full of boiling water on the ice. Never break the ice or you may harm the fish. Floating pond heaters are also useful to keep the surface open.

Observe Your Fish Regularly

Besides being fun, watching your fish on a regular basis is the best way to observe their health and your pond's water quality. Observe and watch long enough and you will know instantly when things are amiss by the action of your fish. And remember … studies have shown that simply watching fish relieves stress and reduces your blood pressure.

Fish Selection

Some of the many species of fish are listed below. Goldfish in their many varieties are by far the most popular. They are affordable, hardy, easy to care for and peaceful. Select the non-fancy varieties of goldfish; those with bulbous eyes, bloated bodies or missing fins are better suited for aquarium life and may not survive winter outdoors.

Koi

The Koi is bred specifically for the pond. All of its color is above the midline, making the fish look better when viewed from above. These fish come in many different colors including red, white, black, blue, yellow and any combination of these colors. Koi can grow up to 36-inches long making them quite visible in the pond. They can also outlive their owners. Most books written about this fish say that they can live to 100 years old. The Koi has an insatiable taste for plants so if you prefer to keep water lilies, hyacinths or other pond plants this fish should not be kept.

Comet Goldfish

This is the most common fish kept in the garden pond. They are generally red but some can have some white or black mixed in. A particularly beautiful variety is the Sarasa comet, which has a deep red and white pattern. Comets grow up to a foot long, making this fish a little more manageable than koi especially if you choose to bring the fish inside or the winter. The comet will also not harm any of the pond plants.

Shubunkin

This fish is a tri-color cousin of the comet. The three colors usually evident on this fish are red, blue and white. The shubunkin grows to a length of between eight and ten inches and is very peaceful. It also will not harm any of the pond plants.

Fantail Sarasa

This bi-color fish is also very peaceful and beautiful. Color is almost always red and white and unlike the previous fish discussed it has a double tail fin, hence the name fantail. The fan tail, though beautiful, does tend to make this fish a little slower in the water and therefore more vulnerable to predators such as raccoons cats and herons, and even rowdy koi.

Rainbow Dace

This fish although not related to the goldfish is still an excellent choice for the pond. Full size is only about two to three inches, making it a good choice for the whiskey barrel or other small pond. Dace make a great fish for mosquito control and look quite striking in the sunlight with their shimmering rainbow colors. Rainbow Dace will also not harm aquatic pond plants. This fish is not considered hardy and should not be left in a freezing pond in the winter.