DWC in fish tank?

Thread starter #1
Hi everyone, I only knew about hydroponics for a few days, and I'm totally fond of aquaponics at first sight because I now have like 5 tanks full of fishes and all over 2 years old, so the biofilter should be no problem. But as a newbie I want to make sure to know things carefully before I get it to work.

So, I want to ask which kind of fish should I use DWC in? I have a goldfish tank, african cichlids tank, livebearer(guppies, mollies...) tank, tetra tank, and oscar tank. I actually prefer the goldfishes because they poop a lot = more nutrients but they're also a bunch of water pigs that devour anything and could harm the roots so what do you guys think?
Speaking as someone who kept fish for 30 years and has grown cannabis in soil, coco, and hydro, "aquaponics" sounds like a fun thing to do that could take a plant through to harvest, but other than being a fun stunt (nothing wrong with that), it seems like a waste of time to me.

I say that because growing cannabis requires time and effort to produce a good crop. Consequently, most people eventually end up trying to optimize their grow. They may start out thinking they'll just put a seed in some dirt and see what happens, or they'll just use whatever soil and fertilizer they have lying around, or the least expensive setup they can throw together--compact fluorescents from the hardware store, cheap home center potting soil, maybe a little Miracle Grow. Or use their aquarium as a source of food and fertilizer.

But the fact is that there is a huge range of outcomes possible depending on how you grow. Yes, a seed in dirt can grow to maturity, but for most people it will end up looking more like a weed than trophy winner. By investing just a little bit more for better soil and/or better fertilizer, results are much better. Then better lights--they make a huge difference.

The questions about how to grow good cannabis have been answered. Everything you need is available at reasonable prices with a click and a credit card from Amazon. You're going to spend a couple of months or more carefully tending your plants, so why not spend the little bit extra to get good soil, good fertilizer, and good lights and have a good harvest for all the work you put in?

I totally get the appeal of putting the fishies to work feeding your plants, and if you want to try it, please do by all means. But don't expect Bud of the Month results.

Some quick notes: If your cichlids are in brackish water, that's a non-starter. And remember that roots don't like light, so you'll probably want to separate fish and plants somehow. And the pH of your fish tank and the ideal pH of your reservoir may not mesh without some work.

Just my .02. Like I said, it's do-able, but unless you're just looking for a fun project, a dedicated hydroponic setup with cannabis-grade nutrients and excellent lighting will give you the results that will probably make you happiest. Or maybe you really do just wanna grow pot in goldfish poop?

I imagine (in fact I hope) there's some crazy pothead fish fancier out there who has a combo koi pond / cannabis farm that's cranking out killer bud for pennies with next to no work. If so, I'd love to hear about it and see the pictures.
Thread starter #3
Thank you Mr.Scientific, and yes, in fact this is more like an experiment to me, mostly to watch how it goes, how much I could learn and improve, maybe someday I could even be that guy with a koi pond/cannabis farm combo, if not being arrested or beaten to death in police stations....
I actually have grown cannabis in soil for years since high school, so I'm never out of buds, and won't really worry about the result. I love the cultivation of this plant and just want to try out every possible ways, and I also like organic growing(I prefer worm-casting in my soil crops over all) so an ecosystem between fish and plant is exactly what I wanted, at least for now.
About the tanks, I kept them all around the pH of 6.5-7, though I don't have to do much because the system already balanced itself. But I might have to get something to cover the net pot area to keep the light away, because the tanks and the grow boxes already took so many spaces, so I couldn't really separate the fish and plant.
Anyways, thank you again for your advises and exps, and my cichlids tank are totally freshwater, but since I never plant anything in their tank I don't know how'd they treat the roots so maybe I'll try out with tomatoes first.
Hey CG -- OK, cool. Well good luck and please post pictures if/when you get something going. It does sound like a fun project. If nothing else, you can just pour the water from your tanks on your soil grow and let all those fishy nitrates do their thing. ;)


420 Member of the Month October 2010 & September 2
There are mainstream (non-cannabis) articles about aquaponics that can be searched for via your favorite Internet search engine. And there have been a number of books published - perhaps your local library has one?

I'd think that you'd be better off keeping the two setups separate, with the cannabis (et cetera) grow serving as one of your... ah... fishtank water filtration devices (IDK the terms :rolleyes3 ). Pump out of the aquarium and into the cannibis plants' containers, then recover that and... IDK, does it require treatment at that point? If you're not applying fertilizers where you'd have nitrogen/phosphorous/etc. in your runoff, then probably not - but that's just a guess.

BtW, the setups that I've seen pictured appeared to have something substantially larger than the average sized aquarium. More like the koi pond that was mentioned. Actually, koi would probably work pretty good because they're just colored carp, lol, aren't they? The carp around here in the rivers (I know, completely different species) are known as trash-eaters. I think... the smaller your fishbowl (lol) is, the less effective it'll be in turning fish food into fertilizer - and the less "buffered" the system will be as a whole. By that, I mean an issue can become more serious, faster.

Again, this is guesswork on my part. I tend to look at fish more as something to catch, cook, and consume (although the environment is really too polluted for that to be a safe practice locally, unfortunately).
I don't know about doing aquaponics with cannabis. But I would think it would work great, if done right.

The reason I say that is that I have a friend with a large outdoor fish pond (koi, I think). He's had it for many years. He found that the water from this pond is crazy good plant food. Lately he's been bringing me a jug of that stinky stuff every week for my plants. Everything I water with it goes wild with new growth - even one house plant that I had just finished pruning back heavily. I really chopped that thing back harshly. It should have been in shock for weeks, but like the rest of my plants it is popping out new leaves all over, and fast!

I just read something the other day about some big time cannabis grower in Amsterdam (Steve something?) doing aquaponics, or some variation, and having great success. Sorry, I don't remember any details.