Protect fish health, follow simple winter pond maintenance tips

PINE BLUFF – Now that winter is here, farm pond owners can take some steps to ensure the health of their ponds in time for spring according to Scott Jones, small impoundment extension specialist at the University of Arkansas at Pine Bluff.

“Smart pond management this time of year will help ensure the health of fish populations,” he said. “There are some precautions and adjustments you can consider that apply to aeration, feeding routines and overall fish health.”

Aeration

“Water is most dense at 39 degrees Fahrenheit (F),” Jones said. “Water warmer or colder than 39 degrees will rise to the surface – this is why ice forms at the water’s surface rather than the bottom of a pond and why deep water stays cooler during the summer. During the winter, running aeration systems, especially those that are also effective circulators, can cool deeper water more than normal. This puts more stress on warm-climate fish.”

In extreme circumstances, especially in shallow ponds, aeration/circulation in the winter months can cause a pond to freeze solid rather than just on the surface, he said. This would kill all the fish in the pond.

Farm pond owners should:

• Turn off aeration systems and fountains when the water drops below 50 degrees F.

• Use any downtime in winter to inspect/replace compressor filters, clean vents and diffuser pads/ sticks and replace any worn parts as recommended by their system’s manufacturer.

• Restart aeration systems gradually when water temperatures rise above 50 degrees F in the spring.

“It’s very important that the process of restarting your aeration system be done gradually, over the course of a week, for example,” Jones said. “Begin the process by running the system for 30 minutes the first day, then turn it off for the rest of the day. For each following day, double the run time until the system is running continuously by the seventh day. Then keep the system running continuously for the rest of the warm season.”

If a system is ever turned off for more than 12 hours, the restart procedure listed above should be followed, Jones said. Adhering to the gradual restart process could prevent a dangerous turnover that kills the fish in a pond.

Feeding routines

“While fish continue to eat and grow during the typical Arkansas winter, they do much less of both during this time,” Jones said. “Feeding routines should be slowed as fish activity at the feeders declines. When you eventually stop seeing fish respond to the feed, you should stop feeding them.”

Jones reminds farm pond owners that:

• Uneaten feed contributes to the pond’s nutrient load without benefiting fish. Excessive wasted feed can lead to worsening aquatic weed and algae issues.

• Feeding is generally only recommended when water temperatures are above 65 degrees F. However, it is not uncommon for fish to continue responding to feed in somewhat cooler temperatures.

Fish health

Jones said fish are generally cold-blooded, which means their internal temperatures match those of their environment. During winter, warm-climate fish can be stressed by the cold, making them more susceptible to diseases.

“Channel catfish commonly develop saprolegniosis, a fungal infection sometimes called ‘winter kill’ or ‘winter fungus.’ Symptoms include yellowish-brown patchy lesions on the skin and sunken-in eyes,” he said. “Losses to this infection can range from a few fish to the majority of infected fish.”

According to Jones, the best prevention method for saprolegniosis is maintaining healthy water quality. Landowners should also handle their fish carefully so as not to remove their mucus coat. The mucus coat is critical in preventing infection and disease, especially in winter.

For more information on pond maintenance, contact Jones at joness@uapb. edu or 870- 575-8185. For local assistance with pond management and troubleshooting, contact your local county Cooperative Extension Service office.