Springtime is a joyous time for all people but few probably look forward to it as much as pond keepers. Since the transition from winter to spring is a gradual one, there will be several stages that can affect the health of your fish and plants. This article will describe these stages and the chores you need to perform to get your pond in top shape.
Once the ice melts and the pond begins to warm, you will need to clean all of the sludge out of the pond. This includes leaves, muck, and other debris that have accumulated and broken down over the winter. This is also a good time to divide or replant your pond plants, since they have just started to emerge and are easier to handle. Remember to fertilize any lily pots to give them a good start. You will want to get your filter system started, and since most of the nitrifying bacteria will have died off, you may want to use one of the commercial bacterial treatments available. The water temperature will need to be at least 50°F for the bacteria to be able to colonize the bio-media. It is also a good idea to get the UV sterilizer system up and running before the pond develops any free-floating green algae. This can help keep the water crystal clear. It will also help prevent the spread of any infectious bacteria.
Water warms to 50ºF
As the fish come out of their hibernation mode, their level of activity will greatly increase. This does not mean you need to immediately start feeding them twice a day or more. Until the water temperature stays above 50°F, you really should restrict any feeding to a small amount early in the day. This will give the fish adequate time to digest the food before the temperatures drop at night. Wheat germ-based feeds appear to be easier to digest in fish with slower metabolism. This is a critical time for the pond, since the fluctuating temperatures will make it hard on all the organisms (fish, plants, and nitrifying bacteria) to remain healthy. Fish are susceptible to bacterial and parasitic problems from the stress of changing temperatures. It is usually a good idea to use a general parasite treatment, but best to only use a bacterial treatment if you actually see problems. Even then, it is best to use a feed-base antibiotic to avoid damaging the newly developing nitrifying bacteria of the biological filtration system. While the biological filtration system is getting up to speed, you may need to add an ammonia-stabilizing compound to the water to help reduce any ammonia toxicity. If needed, you should do a partial water change, making sure to treat the water for any chlorine/chloramines found in the tap water. A good test kit for ammonia and nitrite will be invaluable in monitoring the development of the nitrifying bacteria in the biological filtration system and to help gauge the need for a water change. Remember that this can be a particularly stressful time for fish, so handle them gently and avoid overstressing them.
Warm weather arrives
If you are in a part of the country with bright, sunny days, you may need to provide some artificial cover for your fish until the live plants mature enough to provide natural cover. Artificial lily pads or other floating plants can be used as temporary cover.
Do not be surprised if your pond "trills" at nighttime, it is just the local toads attempting to woo their mates into spawning in your pond, soon to be followed by thousands of small tadpoles that will disappear after a few weeks. Once the biological filter is up and running and the plants are growing, it is a good time to add new fish. Remember that a pond is a living system and fish will add a biological load to your pond so add them a few at a time. This will help the biological filter grow and prevent any dangerous ammonia or nitrite build-up.
A little bit of hard work at this time of year will allow you to enjoy a healthy pond for the rest of the summer. This is one time the return on your investment is well worth the effort. You should also realize that spring is also the best time to dig your second pond!