Backyard Aquaponics
A place to discuss aquaponics

I downloaded a bunch of technical documents on trout farming. It seems you could meet most of the requirements for rainbow trout (using AP) except the water flow rate. The document I'm looking at gives the flow rate for small fish at 1.2-1.8m/min and for large fish 2.4-6m/min. Jeesh! 6m/min comes out to 300 gallons/minute for just a 2x1 foot raceway if my math is correct:

6meters/minute = 19.7 ft/min
in a 2sqft raceway: 40cuft/min = 300 gallons/min. I think we're talking a pump in the 3HP range. How do they do it at commercial hatcheries?

A lot of them are fed directly by a river, no pumps necessary; others probably just have 3HP+ pumps.

There are a lot of trout hatcheries around my area and the stocking densities they use are a lot higher than in most AP systems so their recommendations are probably for those high stocking densities.

Comparing apples and oranges there really, I wouldn't pay a lot of attention.. There are many people here on the forum who have grown lots of crops of trout.. I think she is about to harvest her 4th or 5th crop of trout from her system..

I'm curious how most people obtain them. I tried calling the Fish & Game Dept here in WY. I got transferred to another # (VM) and left a message. No callback. I looked at the documentation and it said the 'pond' should be no less than 1 acre. Apparently the process the hatcheries go through to breed them is pretty involved. They put the females in a bucket of something to knock them out, extract the eggs and fertilize them with the male 'molt'. The fry hatch by the 1000's. They start out feeding them with algae then sea monkies. I think the problem, besides getting them enough O2 would be keeping them cool in the summer. Not so much warm enough in the winter.

Trout do fine until the water gets too warm to contain enough DO. I got mine January from a trout hatchery that usually stocks local streams, that was fed by a spring. The trout never swim in their own waste because this was a flow-through system, not recirculating. Spawning etc. the fish is a different game than just growing them out. For growing them out just make sure the DO is as high as you can affordably get it, I used a linear air pump (like $60 on Amazon), that the amount of fish is not overstocked for your filter volume, and you try to keep the water cool when the weather gets warmer. Mine died from lack of DO in mid-June (in PA FWIW, water temp was low 70s I believe). I plan to get some more trout to grow over the Winter and Spring just as soon as I get a new system together.

Look for local fish hatcheries and call them and ask if you can pick up a few. I got 35, took them home in a cooler with an air pump running from the car using a little inverter.