Once hatching begins (normally 6-7 days after arrival), in most cases with Troutlodge eggs it will take a period of 2 to 4 days for all eggs to hatch. The exact amount of time it takes for all of the eggs to hatch depends on water temperatures and hatchery conditions, as well as the individual lot of eggs. Once again, it is important to quickly remove the shells left behind by the hatched eggs.
In the rare case that you experience premature hatching either in the box or immediately after transfer into your hatchery, it is important to try to save these fish. While the fish may be hatching early, in most cases they are still viable fish that with proper care will behave and grow like a fish that hatched on a normal schedule.
The next step at this point depends on the type of incubation units being used.
If hatching troughs are used, the sac fry should be transferred to the separate rearing units shortly after hatch-out is complete. Many farmers simplify this process by using oblong holes in the bottom of the troughs, allowing the sac fry to simply fall through the screens into the rearing unit.
If upwelling incubators are used, the flow in the incubators will naturally force the sac fry out of the upwelling jar and into the rearing unit. In addition, the upwellers will expel the shells, making it easier to keep the hatching unit clean.
If vertical incubators are used, it is ok to leave the sac fry in the trays until swim-up, at which point they should be carefully transferred into a larger hatchery unit.
Once the eggs have finished hatching, they will take ~10-14 days to absorb their yolk sac before swimming-up and beginning on a commercial trout diet. The initial presentation and acceptance of food marks a critical stage of development for trout culture. Because this is such a critical time in the development of the fish, we recommend use of the finest starter diets available to you. Feed size, shape, ration, presentation method, and feeding frequency all play important roles in the production of rapidly growing, healthy rainbow trout fry. For more information on the optimal feeding and handling practices at this stage of development, please refer to the details provided in the Troutlodge Technical Bulletin titled Early Rearing and the SRAC bulletin Handling Eggs and Fry. Both can be found in the Useful Links at the bottom right of this page.
Once the fish have successfully been introduced to feed and have shown good growth, rearing strategies depend largely on the resources available to you. However, regardless of the stage of development, it is always critical to utilize best practices in feeding, biosecurity, and handling in order to minimize the introduction and/or the effects of disease and to maximize growth and marketability. Please consult the Troutlodge Technical Bulletins or contact us at any time for more information.