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.