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Fish: To Eat or Not To Eat

January 15, 2010

Yesterday I was asked why someone would grow aquaponically.  I went through the usual reasons that we probably all use to justify the time and money we spend on our obsession – organic produce that is sustainably grown, the ability to garden anywhere, regardless of soil quality, without mess or weeds, etc., etc, etc.  I found myself wrapping it all up, however, with the heartfelt exclamation “but the real reason is that it’s just fun!  I look out at our landscaping and my flower gardens and think how I enjoy the flowers, but it’s pretty static and, worse, it doesn’t greet me in the morning”.

tilapia (from

tilapia (by Rebecca Nelson)

Fish are clearly the heart and soul of an aquaponics system.  They don’t ask much of us – oxygen, water in the right pH and temperature, and food – and they give our plants life.  And perhaps the best part is how excited they get when I go into the greenhouse and it’s feeding time.  The mature tilapia all crowd around where I usually throw in the food and wait at the surface.  Then the frenzy ensues as I feed them.  A little bit of the wild kingdom in the otherwise tranquil greenhouse.

So I pose the question – to eat or not to eat?

When you select the fish for your aquaponics system the first decision you make is whether your fish are destined for your dinner plate (tilapia, catfish, trout) or are strictly ornamental (koi, goldfish).  I’ve found, however, that as I’ve lived with my aquaponic systems those lines are no longer so clear.

I’ve been growing tilapia since April.  I’ve had visions of a dinner party with freshly caught tilapia as the centerpiece since day one.  Problem is, these fish and I have been through a lot together and I’m afraid we are bonding.  I admire their ability to endure the half a dozen ways I almost killed them over the summer (ends up they really can recover from electric shock!).  I enjoy their elegant beauty as they float through the tank and their hunger-induced enthusiasm for my greenhouse visits.  While I still joke about their future, I joke with less conviction these days.  To eat or not to eat?

tilapia for sale at Growing Power

Now I’m considering getting a couple pacu.  They have a reputation for being wonderful food fish – internet stories of barbequed pacu ribs made my mouth water.  They are being raised on farms in South America for this very purpose.  Pacu are vegetarian members of the piranha family that eat just about anything (table scraps) and are incredibly fast growers that will reach 18” in about a year.  Great metabolism = lots of plant food and a fast journey to dining nirvana.  And yet…. they apparently also love to be stroked and will greet you at the tank’s edge like a koi.  To eat or not to eat?

Pacu (from

I discussed all this with the manager of a local pet store who has a long history of raising fish.  He pointed out that actually many fish they sell as ornamentals are treated as food fish in South America.  Tilapias are cichlids, and there were at least 5 varieties of “fancy” cichlids displayed in fish tanks for fancy prices at the pet store.  Oscars are the in the same category – pets in the U.S. while being dinner plate fodder in South America.

So when you are figuring how to stock your next aquaponic system (see last post on addiction) and you are trying to decide “to eat or not to eat” my advice is not to worry about it too much.  You can always change your mind.

2 Comments leave one →
  1. tokyobling permalink
    February 18, 2010 10:37 pm

    Love this blog, can’t wait for more updates! One thing that always bothered me in these discussions, raising fish, is how to make sure enough fry is born and survive to stock the next population of your tanks? I read that these fish are fast breeders, but how do you personally handle pregnant females, the resulting fry and caring for the fry? Would love a blog post on this! Cheers, and thanks for a great blog!

  2. February 23, 2010 8:20 am

    Tamper them when it still alive,eat them when the time come,you know what i mean,he he….

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