Can you grow trout in a 150 gallon tank?

[Tom OBrien]

I'm relatively new to aquaponics and would appreciate any suggestions or feedback on the feasibility of growing trout indoors in a relatively small 150 gallon stock tank. I was thinking I could stock 15 or 20  6-8" rainbow trout from a local hatchery.

I am currently running a setup with the goldfish from our small backyard pond, but I'd like to grow some fish we can eat. The temperature in the basement should keep the water cool enough for trout. I figured I could keep the water moving with a pump and provide plenty of aeration, and cycle it fishless. Is there any reason this wouldn't work?

Tom

[Tom OBrien]

I've managed to keep most of the trout alive for three weeks, but their feeding has slowed down some and one went belly up in tank 1 yesterday with another in tank 2 swimming kind of sluggishly on his side. The ammonia and nitrites are still between 0 and 0.25 ppm in both tanks, the temperature is about 66 degrees, and the air pumps and water pumps are all working. pH in tank 1 appears to be stable at about 7.8 and while the other has gradually come down to about 7.0 since I started cycling. I'm not that worried that I lost a couple but I am a little concerned that the rest don't seem to be feeding as aggressively. Could it be that I am simply feeding too much for the temp and O2 levels?

[Tom OBrien]

An update on my 150 gallon tank Trout Project. I added a tank, cycled it fishless, and I've had the trout in the two tanks for 13 weeks now.

There were a couple problems along the way, like having six fish die on the basement floor the first day because I hadn't really figured out how I was going to cover the tank before I put the fish in. I brought home the 25 trout and got them in the water, walked upstairs to find the netting in the garage, and came back down 10 or 15 minutes later to find two of them lying still on the floor. I thought I had the cover secure enough, but the next day I found four more had escaped through gaps around the pipes. Not a very good start.

I went a little slow with the feeding initially because one system was new with just some seedling in the grow beds and established system with some mature plants had less grow bed volume. That probably is what has caused me to be way behind the growth rate estimates of the more experienced trout growers. With all the hot weather we've had, my water temperature has slowly risen from 65F to about 72F which may also be slowing growth a bit. The fishless cycling, light stocking density and cautious feeding have probably been helpful with water quality in the smaller tank

Now I am thinking about starting to harvest the fish. Growth rates in the older tank have been more uneven. The largest fish there is probably close to the 1 lb mark (success!) while the smallest probably weighs 3 or 4 ounces. In the other tank I think they are all between 8 to 12 ounces.

I appreciate all the helpful comments. This project has been a lot of fun.

[James Keller]

Hey Trout Growers,  I've got a little basement system set up with locally-caught trout.  I captured them earlier this summer as minnows/fry and they were all about 1 inch long.  They were in a small, 15 gallon tank until about 45 days ago, when I moved them all into a 110 gallon stock tank in my new, larger system.  Right now they are averaging 1 1/2 inches long, some are getting to be 2 inches long.  

My questions are - At what size should I start to harvest them?  How long should that take, given the parameters below?  How much should i be feeding them?

I've got a 45lb bag of trout pellets from a supplier in Denver.  The pellets are 7.5mm (huge compared to the fish) so I've been chopping them down to almost a powder with a coffee grinder (any better ideas to get the pellets down to size?)

PH is 6.8

Water temp is in the low 60s

110 gallon fish tank with roughly 25 1 to 2 inch trout.  110 gallon sump tank with a few buckets filled with porous material for bio-filtration.  2 50-gal grow beds, one filled with hydroton and the other floating raft. 

Hopefully these questions aren't too open-ended.

Thanks for any help,

James

[Tom OBrien]

James - I started with 25 rainbow trout that were about 6 inches long and had them split between two 150 gallon tanks. I lost 12 along the way to various mishaps and harvested 3 in the last two weeks. I have had the rest in the tank for 17 weeks now.

The growth rates have been pretty uneven though. Some of the fish look like they are still under 8 ounces while the first one I harvested was about 20 ounces. I am shooting for 1 lb for harvest size, but we ate the jumpers who were closer to 3 ounces and they were all good.

Because your grow bed volume and tank volume is small like mine, you may want to harvest some early if you have trouble with water quality. My second tank was new and didn't have established plants, so I stocked light and fed kind sparingly at first. Some of the more experienced trout growers commented on how fast trout grow from 8 to 12 inches, but most of mine grew more slowly for whatever reason. Good luck!