Using spent aquarium water on fruits/veggies

My daughter has a 20 gallon aquarium full of goldfish and quarry cats. Of course it’s daddy’s job to clean it. So I’m doing a drain and fill this morning and got to thinking about the use of the aquarium water on my plants, namely my potted figs, potted apple grafts and my blueberry bushes.

We don’t use any chemicals in the tank at all. The water is pretty much saturated with fish poop aND un-eaten fis flakes. Probably high in ammonia. Seems like many people spend a lot of money on fish poop sprinkles fertilizer so this in theory should be some pretty good water.

What are your thoughts?

I pour my used my aquarium water on my flower bed near the front door (closest door to the fishtank). The irises there thrive on it. I do 30% water changes ideally twice a month.

I hate to waste it down the drain. Its good stuff. I’d say go for it.

Good to know. We change ours about once per month and normally replace about 2/3 of it. The fish don’t seem to care either way. We’ve gotten a lot of rain so my plants don’t need any water right now. But I’ll use it when things dry out a bit.

Yeah, for the last eight years that I been using dirty fish tank water on my Peach and persimmon trees. I don’t want to waste all that nutrients from the 180 gallons tank.


I used to have several fish tanks. My houseplants did great on the water, especially the amaryllises. My edibles were too far from the house to lug the water to them.

Absolutely… aquaponics is a method that combines fish raised for food using the fish water in the hydroponic section for food crops
Google aquaponics for loads of info


Some of you probably already do this, but we got a small aquarium for the kids this year. I found that aquarium water makes our potted citrus very happy. It seems to work better than Foliage Pro does. These plants also have Oscamote Plus granules feeding them.

I don’t have a before picture but if you can see the less pretty leaves, there were lots of those before I started putting the occasional aquarium water in there.


We use water from our red slider all the time to fertilize plants. Seems to work really great!

Just started using the dirty tank water for my seedlings. Anyone know if there’s anything to be concerned about with the dechlorinating additives?