The Tao of Tiny Tanks

Every aquarist knows that a large fish tank is more attractive and easier to maintain than a small one. But small tanks do have their benefits; and it's worth every decent aquarist's while to keep one.










Ask any experienced aquarist what the ideal aquarium size is, and you'll almost surely hear something along the lines of, "the bigger, the better." I'm not about to contest this. It is, after all, a scientific fact--more water volume means more stable water chemistry, which in turn translates to higher survival rates in your fish stock; simple. However, I've never been a fan of taking the easy way right off the bat. In my book, the hard way offers more lessons. And once you weather the difficult stuff, everything becomes easier. It's no surprise then, that as I understood more about the benefits of going with a large fish tank, the more I got interested in having small (actually, "tiny" is the more appropriate term) aquaria.

Tiny fish tanks--5 gallons or less--are like drill sergeants to an aquarist. They give you basic training on fish keeping, and they make you pay dearly for every single mistake. I've experimented with tiny tanks over the past several months, and in that time a good number of fish have given their lives so that I may gain a good grasp of such things as water chemistry, bioload and plant-and-animal symbiosis--the basics of how to keep healthy fish. Now, with three thriving tiny tanks (two one-galloners and a two-gallon), here's what I can share with those who are thinking of setting up a small aquarium:

1. Never go under 1 gallon. Yes, there's a limit to everything. And although tiny tanks can make good homes for fish, keeping even the smallest fish in anything smaller than a one-gallon tank or fish bowl is just downright animal cruelty. Personally, I recommend something between two and five gallons.

2. Make it an NPT or nothing at all. NPTs (or Natural Planted Tanks) are the only way to go when you're talking of tiny tanks. Formulated by veteran aquarist Diana Walstad, the NPT concept does away with all the usual aquarium contraptions, such as mechanical filters, chemically enhanced substrates, supplemental CO2, and artificial lighting. Instead, it relies on the natural symbiosis of plants and animals to maintain a stable ecosystem and good water chemistry. Plants provide biological filtration, fish provide CO2 and fertilize the plants with their waste, and the sun provides lighting. Aside from helping you save on equipment costs, the NPT concept plays right into tiny tanks because it allows you to maximize the limited volume of the tank--no filters or other contraptions to take up valuable tank real estate. More importantly, tiny tanks hold so little water that only the self-balancing nature of an NPT will spare you from having to make daily water changes.

3. Floating and emersed plants are musts. Many aquarists around the world swear by the water-purifying properties of floating and emersed aquatic plants. Nature enthusiast and blogger Tunc Ali Kutukcuoglu presents some very interesting facts about this in his article, "Indoor Plants for Water Purification and Nitrate Reduction in Aquariums". And, considering how quickly the water chemistry in a tiny tank can go from less-than-ideal to outright deadly (I've had perfectly healthy fish die within hours of being placed in a bare fish bowl), you simply can't go without such plants in a tiny tank.

4. Stock conservatively. In larger planted aquaria, such as my 20-gallon community tank, a little overstocking is forgivable, provided you do your water changes frequently (I do mine weekly) and religiously. But this is absolutely NOT the case with tiny tanks. I recently stocked my 2-gallon tank with 3 inches worth of fish--a 2-inch dwarf gourami and a 1-inch guppy--and the guppy died within 48 hours. With tiny tanks, the 1-inch-of-adult-fish-per-gallon-of-water rule is non-negotiable. And if your tiny tank happens to be odd-shaped, such as a bowl or a tank that's higher than it is long, go by the surface area method: one inch of adult fish per 12 square inches of water surface area.

5. Choose only small and hardy fish. Contrary to popular belief, a fish bowl is NO place for a big-bodied, messy fish like a goldfish. For tiny tanks, only small, thin-bodied (i.e., laterally compressed) fish of the hardiest species will do. Species that have done well in my tiny tanks are the dwarf gourami, red serpa, guppy, platy and betta. Aside from being small, these species are relatively docile, spending most of their time casually swimming about the tank. I've also had success with a zebra danio in my 1-gallon bowl, but I wouldn't recommend it. Zebra danios are active fish that love to dart back and forth, and thus need lots of free swimming room; keeping one in a tiny tank would be like keeping a thoroughbred locked up in a stable all his life.

6. Feed very sparingly. It may sound cruel at first, but scrimping like Scrooge with your fish food is actually better when you have a tiny tank. Think about it. At most, you'll have five one-inch-long fish in a 5-gallon tank.They certainly won't consume too much food at any given time, which means that overfeeding will only result in uneaten food polluting your tank water. Besides, your tank will be planted. And if you have the right fish species in your tank (as mentioned above), they'll all have no problems feeding on algae and other plant matter in case they get hungry. My own tiny tank inhabitants have done very well with one feeding every two days; or once a day at most.

7. Change water every week. Adopting the NPT concept, and having floating and emersed plants, does not change the fact that a tiny tank holds a minuscule amount of water. So, although an NPT of 20 gallons or more can go for months without a single water change, tiny tanks are not so forgiving. My own 1-gallon bowl kept my betta healthy for over a month with only an occasional top-off, but that was more of an experiment to see how long the tank could go without water changes. My regular practice is to do a 20-percent water change every week on my tiny tanks. If you can manage it, a 10-percent water change twice a week would be even better.

Just as you would choose a sprawling villa over an apartment any day, any fish will always be happier in a larger tank. But then again, just as you won't really feel imprisoned living in an apartment, a fish can fare quite well in a tiny tank. And for an aquarist, tiny tanks offer a good many benefits: they're cute and space-saving; maintenance takes less than 10 minutes at a time; and they're cheap to set up. But the most important benefit of all is that tiny tanks provide a pleasant learning experience--not just in the science of fish keeping, but also in the virtues of patience, restraint and discipline.