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Raising fish in a lined trench

I'm starting to design my first system. It will be in my backyard. I live in central Florida so heat is a consideration. I'm leaning towards digging a trench and lining it, however I could use advise as to construction techniques and dimensions.
Thanks, rob

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Replies to This Discussion

Permalink Reply by Jane on March 17, 2012 at 5:31pm

are you growing fish or plants in the trench

Permalink Reply by Rob Boone on March 18, 2012 at 9:24am

It will be for the fish. The reason is to maintain a lower and constant water temperature for the fish.

Permalink Reply by Jane on March 18, 2012 at 12:03pm

I think it is a good idea . find out how deep the fish need it to be to not jump out . there is a video of a new commercial project in Santa cruz that they dug out the ground for big tanks it might give you some ideas.

http://www.youtube.com/watch?v=fAiEw2Uflv4 i alwaays like to watch different videos for ideas

Permalink Reply by Sheri Schmeckpeper on March 19, 2012 at 8:59am

What fish will you be raising, Rob? Tilapia do well in water 3'+ and they are great jumpers. If your raising tilapia, you might consider digging down an extra foot+/-, or you'll want to create a cover of some sort to keep them in.

We're in the AZ desert and have our tank sunk in the ground. It does help a lot to keep the temperatures consistent.

Permalink Reply by TCLynx on March 20, 2012 at 8:00pm

What sort of plant method will go along with the fish?

I ask because flood and drain grow beds or towers or nft will greatly influence your water temperatures during the cold spells at least in inland central FL.

Be sure your in ground tank is deep enough but also make sure the top edge is enough above grade to keep heavy rains from washing ground water into your tank.

I'm personally a big fan of channel catfish and/or bluegill here in inland central Florida since they can take the heat and the cold, they are native, they taste good, and at least the channel catfish grow big and fast.

Permalink Reply by Rob Boone on March 21, 2012 at 12:30pm

I was considering flood and drain. Do you have another suggestion? Also thanks for the great advice. Rob

Permalink Reply by TCLynx on March 22, 2012 at 7:14am

Flood and drain media beds are good. You just have to figure the water level fluctuations and know that most of your heat exchange will take place in the flood and drain media beds so having the tank in ground will only help with temperatures a little bit. So far in Central Florida I've found that as long as I choose an appropriate fish type, as long as my fish tank is over 300 gallons, I've been ok with the temperatures. Even in ground I'm afraid a smaller tank would run into problems though.

In a more extreme climate than inland central FL, one might want to have a larger amount of water. My big system with 700 gallons of fish tank is very stable.

Permalink Reply by Rob Boone on April 7, 2012 at 9:50am

TCLynx said:

What sort of plant method will go along with the fish?

I ask because flood and drain grow beds or towers or nft will greatly influence your water temperatures during the cold spells at least in inland central FL.

Be sure your in ground tank is deep enough but also make sure the top edge is enough above grade to keep heavy rains from washing ground water into your tank.

I'm personally a big fan of channel catfish and/or bluegill here in inland central Florida since they can take the heat and the cold, they are native, they taste good, and at least the channel catfish grow big and fast.

Permalink Reply by Rob Boone on April 7, 2012 at 9:53am

Thanks, channel cat seems like a great idea. Have you any experience with crappie? Also, I've heard from several people that tilapia are not legal in Florida. Is this true?
Rob

Permalink Reply by TCLynx on April 8, 2012 at 6:11am

No I don't have experience with Crappie.

I have experience with Blue Tilapia, Channel Catfish and Bluegill.

Only Blue Tilapia are sort of Legal in FL. The Tilapia are over rated in my book unless you are in South FL or on the coast in central FL. They require the water really warm to keep eating and feeding your plants and in my book the best growing season in FL is the cool season so I prefer fish that are happy and eating in water down in the 60's F.

Permalink Reply by David on April 23, 2012 at 8:40am

Well water temperature regulates the surrounding land mass at a given depth. Depending on where you reside in Florida you may only need to go down 3' but in other places you may have to go 6' or more. Check on Google for a well water temperature map for your area. Then find out what how deep your water table is where you want to put the pond. That will give you a rough guide on how deep you need to be for your pond to be temperature stable. Don't forget to adequately shade the ponds from direct sunlight.

Tilapia are a fun fish but I would check with Florida Fish & Wildlife Department before attempting to stock them or order them. Tilapia is considered an invasive species in the Gulf Coast regions. We are only allowed to stock Mozambique Tilapia here in Texas and we must have a permit for that as well depending on the location of the stock tanks. If memory serves there is a gentleman somewhere in Florida that sells breeder colonies for Mozambique but I think the prices were a bit high.