Spring and Fall are excellent times to stock trout in recreational ponds. However, stocking trout without knowing if they are appropriate can be disastrous. A fish kill can result either immediately or in the future without an understanding of specific pond and fish species characteristics.

Rainbow trout are a preferred species by pond owners in Western North Carolina. However, some pond owners stock trout only to later discover the pond is not appropriate. Water temperatures exceeding 70 degrees F for more than a few hours can be lethal to rainbow trout. Many ponds in Western North Carolina exceed 70 degrees F due to inadequate water flow.

Adequate water flow and an understanding of water temperatures during the Summer months are a necessity in selecting an appropriate fish species. In ponds known to exceed 70 degrees F in the Summer months, two options are available. Rainbow trout can be stocked in the Fall when water temperatures consistently fall below 70 degrees F. The trout must be harvested or removed before the water temperature exceeds 70 degrees F in the Spring, usually in April or May.

Cage culture is an alternative and simplifies feeding and harvesting the trout if the pond is at least 6 feet deep and the cage can be anchored in an accessible area. Round cages (4 feet by 4 feet) are widely accepted and can be stocked with 300 trout, 5 inches in size in the Fall. By Spring, these trout will be 10-14 inches, depending on water temperatures and feeding rates. The cages can be built for about $60 or can be purchased for about $100.

The second option is stocking a warm water species. Largemouth bass, bream (bluegill), and catfish are examples of warm water fish and prefer water temperatures ranging from 70-80 degrees F.  Stocking rates are variable, depending on several factors like water flow, pond size, harvest methods, and management preferences. In general, trout must be fed due to natural food limitations. It is optional to feed warm water species. Obviously fish that are fed will grow more rapidly than fish allowed to forage for themselves. Also, generally twice as many fish can be stocked if fed.

Appropriate stocking rates are shown below. A floating catfish feed is available at most agricultural suppliers (about $25 for a 50 lb. bag) and is adequate for the warm water fish species. A standard floating trout feed is preferred for trout and costs slightly more (about $40 for a 50 lb. bag). Fish feed comes in different sizes and the appropriate size feed should be selected according to fish size. Buy only as much feed as needed for one to two months and store in a cool, dry area. If feed becomes moldy, discard it since moldy feed will kill trout. Do not overfeed because wasted feed contributes to water quality problems. Feed only as much as is readily consumed within a few minutes by the fish.

Once an appropriate species has been selected and purchased, the next step is the actual stocking. Temperature differences between the transport water and the pond water can result in immediate or delayed fish mortality. Temperature shock is one of the most overlooked items in stocking fish and can ruin the best of plans. The water the fish are in should be brought (tempered) to within 5 degrees F of the pond temperature prior to stocking for best results. If there is considerable difference (15-20 Degrees F) between the transport water and the pond water, take one hour or more to gradually adjust the temperature while watching for fish distress due to inadequate aeration.

Number of Fish Per Acre of Pond*

Rainbow Trout** Optional Stocking Rate 10 trout per gallon per minute of flow

* one acre = 43560 square feet (210 feet by 210 feet)
** only if conditions permit – it is not recommended to stock both warm and cold water species in the same pond

Optional Stocking Rate 10 trout per gallon per minute of flow

* one acre = 43560 square feet (210 feet by 210 feet)

** only if conditions permit – it is not recommended to stock both warm and cold water species in the same pond

Written by Skip Thompson, Area Specialized Agent, Agriculture - Aquaculture
Read more at: https://haywood.ces.ncsu.edu/ShouldIStockMyPondWithTrout/