Fish Species at

Unfiltered Fish Tanks

Technology seems to be what the aquarium hobby/industry is all about these days.

August 27, 2012

Printer Friendly
Keep shrimp and other algae-eaters in unfiltered fish tanks.

Technology seems to be what the aquarium hobby/industry is all about these days. Manufacturers are always coming out with the latest and greatest filter, pump, light or additive. I may be an old fuddy-duddy (actually, I am an old fuddy-duddy), but I think that in all of this we tend to lose sight of the basics of keeping fish in glass boxes—and nothing brings us closer to real fishkeeping than an unfiltered aquarium.

I have been fortunate in that my wife, Saint Janet, has put up with me and my fish for many years. We have a large house, so I have been able to have many tanks scattered all around, in addition to the fish room itself. I have always had at least one tank that has no filter (and usually no heater) on it: just a tank of plants, fish and some invertebrates.
Right now I have on my desk a small tank that has some cherry shrimp in it, with lots of plants. I also have a 29 gallon with loads of plants and male Tequila Sunrise guppies, honey gouramis, some large neons, shrimps and snails. Both of these tanks are doing beautifully, with no filter, water movement or heat.
Now I realize the typical reaction to the notion of displaying an aquarium without any equipment is, “Wow, what a stupid idea! The idea of our store is to sell all that equipment!” I completely understand that reaction, and I agree that stores are in business to sell all that stuff. But I would argue that having a single tank without any filter (and maybe without a heater) can be used as an excellent illustration of what good fishkeepers you and your store are. A small sign on the tank can explain that unfiltered tanks are only for advanced aquarists; that this is something to look forward to and not anything for a beginning or intermediate hobbyist to try.
Use the unfiltered tank to illustrate the dynamics of how an aquarium works, especially the nitrogen cycle. Point out that live plants, shrimps and other algae-eating beasts are needed in any tank. Also emphasize that you can’t keep as many fish in an unfiltered tank as you can in a filtered one, and that feeding has to be done very carefully.
The aquarium hobby is making a comeback, and a lot of it is due to kids responding to the “theme tanks” tied to cartoon characters, glofish and other technical achievements. Let’s just hope that some of those kids really get hooked on fish—and a tank without a filter, with lots of live plants, shrimp, etc., can also be very appealing to them.

Printer Friendly

 Give us your opinion on
Unfiltered Fish Tanks

Submit a Comment   Join Club
Earn 1,000 points! What's this?
Reader Comments

Ben    Joliet, IL

1/1/2016 5:43:47 PM

I put about an inch of gravel down, and buried an airator in it, then put down an inch or two of soil from my garden, with worms and all. Then I carefully filled it with rain water. After the worms went back into the soil I added a couple of plants a pair of assassin snails and a feeder goldfish. I have a water pump with the filter out and keep the tank a couple inches low to enjoy the waterfall effect and tranquil splashing sound. I only run it when I'm watching it. I put the filer in it when the tank looks cloudy. Recently I added a mystery snail, 2 Koi, and a fancy goldfish. The new goldfish died a couple days later, but the Koi's are doing fine.

LJ    Olympia, WA

1/31/2015 8:51:56 AM

My indoor tanks have filters but I have a half whiskey barrel for which I only add a filter when the weather gets hot to help aerate the water. I put the filter away in late fall before the frosts arrive. There is no better way to clean the water than having the rains overflow the barrel. I have lots of plants, lots of snails and one goldfish. It's very low maintenance.

Tao    Saint paul, MN

11/27/2014 11:14:59 AM

I have been setup tank at the year each summer (not glass tank its more like a big container). I put soil at the bottom and grow plants on it. it turns out very good and if you're worry about insect such as mosquito, put some guppies and don't have to feed them, they will go for the mosquito larvae, and they will reproduce crazily if you have lots plants. for a while, surface will have some films and particles, i just add more water and let the water overflow the container to get rib off the films. For best result, adding submerged, emergent and floating plants.

Anthony    Tampa Bay, FL

9/27/2013 2:29:36 PM

I ran my 56G column tank as an Amazon biotope for over about a year and a half without filtration, only running an air pump with a bubble tube. I had plants, tetras, catfish, and an albino bristlenose pleco. As the author said I had to keep my fish load lower, and recently started running my filter again to increase my number of fish. The plants have continued to thrive, and help maintain the waste level low. I recommend it to everyone to try!!

View Current Comments

Top Products