Raising Rainbow Trout?

[Cai Robertson]

     I am wondering about raising Rainbow Trout and am not finding much information.  From what I have gathered they need cold water, not going over 68 degrees in the summer abd need good water movement and aeration.  The bottom of my tank will be 5 feet into the ground with the water level being 2 to 3 feet higher.  My plants will be about 3 feet over the water level and coverd by a greenhouse, the tank essentially being the foundation of the greenhouse. I live in Barrie, Ontario and would like my system to function year round with minimal heating.  The size of the tank would be at least 1500 gallons so I could easily add extra grow beds (out side of the greehouse) in the spring.  I am thinking it would be best to harvest and restock the fish in the late fall as that is a good time for the fish to be stocked and would coencide with the harvest of many plants.   The smaller fingerlings would then be ample to support the plants within the greenhouse through the late fall, winter and early spring.  I don't know much about the life-cycle of Rainbows so I am hoping for some advice.

[Cai Robertson]

I keep reading that there are 7.48 gallons in a cubic foot.  This does not sound right to me.  Anyone want to weigh in on this one?

[David Waite]

That is right Cai on the ratio.

Cai Robertson said:

I keep reading that there are 7.48 gallons in a cubic foot.  This does not sound right to me.  Anyone want to weigh in on this one?

[Harold Sukhbir]

Hi Cai,

That's a for a US gallon. If you're using imperial standard it will be less.

[Cai Robertson]

I just picture a gallon jug and then a cubic foot and can't see getting any more than 4 in there.

David Waite said:

That is right Cai on the ratio.

Cai Robertson said:

I keep reading that there are 7.48 gallons in a cubic foot.  This does not sound right to me.  Anyone want to weigh in on this one?

[JD Sawyer]

I have been raising rainbow trout in Colorado since the fall and we are actually harvesting in two weeks because the water temperature is starting to push 65F on warm days. The coldest the water ever got was 39 degrees in winter and was unheated throughout. You are correct that they require cold water, high DO and good water movement. Proper filtration will also be key and I would minimize the stocking density to at least 1 fish to 10 gallons to be on the safe side. When we stocked in the fall they were between 8 to 10 inches and they are all now between 12 to 14" perhaps longer. They eat aggresively under good system conditions. We fed them a combination of a pelleted food, snails that naturally occured in the system and worms from our vermicomposting setup.  

 

With cold water your bio-filter will be challenged as nitrification slows down significantly. Keep an eye on nitrite levels and if they creep up past .5ppm then eliminate feed for a day and it will go down. Watercress grew really well in this arrangement but many plants will not respond well too the cold water so you have to be selective.

[TCLynx]

There are many great cold weather crops as long as they get plenty of sun and are not freezing.  I found Broccoli, swiss chard and lettuce, did well in my system through winter as well as the water cress of course.

[Cai Robertson]

     Thanks JD.  My main goal is raising a variety of vegetables including heat loving ones like peppers in the greenhouse during the summer.  I may have to re-evaluate the idea of using Rainbows.  I need a fish that won't limit my vegetable choices and can endure some colder temperatures in the winter.  What kind of tank are you using?  Is it  in-ground?

[Cai Robertson]

Kale and cabbage should do well also.  Do you expand your system at all in the summer? I am thinking I could add some beds ouside of my greenhouse in the late spring(covered in some way of course from the rain).  I am hoping the fish would be growing enough to accomidate this.

TCLynx said:

There are many great cold weather crops as long as they get plenty of sun and are not freezing.  I found Broccoli, swiss chard and lettuce, did well in my system through winter as well as the water cress of course.