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Tiny Fish Tanks

The Problems Inherent in Small Fish Tanks

(The First Tank Guide)

Fish tanks under ten gallons can only be recommended to very advanced aquarium keepers who have a lot of experience caring for fish tanks and aquarium fish. These advanced aquariists need to understand the risks involved in caring for such small fish tanks or bowls. These aquarium experts also must be ready for the challenge and extra work and maintenance a small fish tank like this represents. An expert aquarium keeper who has decided to take on the challenge of caring for a small aquarium also needs to not be concerned about the cruelty inherent in such a small aquarium.

Why Do Pet Stores Sell These Small Aquariums?

Manufacturers and pet stores respond to consumer demands. That's really the simplest explanation of why these products continue to be prevalent on the market.

Consumers - the people who buy fish tanks and aquarium supplies - demand that small aquariums are made available. These same consumers demand that people tell them, whether it is true or not, that these small fish tanks are good for beginners, that small tanks are inexpensive, and that small tanks are easy to care for.

Unfortunately, each of those three statements (above) is untrue.

  1. Small fish tanks are much more difficult to care for. The larger the fish tank, the lower the maintenance, and once you get below ten gallons (about 40 liters) in total tank volume, the care and maintenance increases very very steeply. However, this is not what people want to hear, so manufacturers tell people what people want to hear, and as a result, the manufacturers sell a lot of very expensive small tanks to consumers who don't bother looking for accurate information or researching either aquarium products or fish care first. Then the majority of those people run into a lot of problems trying to take care of the tank, get fed up, and quit. These people then assume that it is impossible to take care of a fish tank and have a nice, easy, relaxing aquarium. But, in fact, it was the demands of the consumers as a mass that the manufacturers lie to them that caused the problem in the first place.
  2. Small aquarium also tend to be more expensive. In fact, if you Aquarium Kit Prices by Aquarium Size look at comparable aquarium equipment, and look at getting all the equipment your fish tank will need, you will almost always find that the absolute lowest price is actually a ten gallon system. As you get smaller than ten gallons, the equipment becomes more costly. At the same time aquarium equipment does not miniaturize well, so not only do you pay extra for getting your aquarium supplies miniaturized, but you also end up buying equipment that is less reliable and more fragile and fickle. So, once you have everything you need, you've ended up spending more money, not less...
  3. Good beginner aquariums are in the 15-30 gallon (about 60-120 liter) range. Once you have a tank this large, you are large enough that the tank can be expected to stabilize and cycle, and you have enough room to safely house a small group of small fish or a couple of slightly larger fish in a healthy environment.

Many of the better pet stores will not even stock an aquarium under ten gallons, and even more will try to discourage people from buying these tiny fish tanks since they are so difficult to care for and so likely to result in failure, frustration, and disappointment. Good pet shops want their aquarium customers to be happy with their new fish tanks, and will encourage the customer to buy a more appropriate beginner aquarium.

Small Fish Tanks and Aquarium Population

Aquarium population is a major concern with fish tanks, especially with new fish tanks and especially with beginning aquarium keepers.

Aquarium population issues are actually compounded by small fish tanks. The smaller the tank gets, the greater the impact of tank population on the fish - the more likely you are to lose fish or have problem because of overpopulation.

Even the smallest fish available in the pet trade really require at least two gallons (about 8 liters) of space each at a minimum. And most of these smallest fish are schooling fish and need to be kept in groups of at least three, but preferably five or more. This space issue alone will clearly show that tanks under 6 gallons (about 24 liters) are absolutely not suitable for keeping fish.

It is interesting that one manufacturer of tiny, high maintenance aquariums recommends that you need at least a 6 gallon aquarium to keep any fish at all. This leads to the obvious question of why they would sell a tank that is only three gallons with instructions that say (though indirectly) that you will need a tank at least twice the size of the one they're selling you if you want to keep fish... Even their own recommendations actually tell you to get a larger tank...

What's the Deal with Ten Gallons?

Ten gallons (or about 40 liters) seems to be a breaking point. At this capacity or above, aquariums seem to stabilize and cycle, and with proper care can be a healthy environment for keeping fish, as long as you keep up with the regular aquarium maintenance and maintain a reasonable population of fish.

At volumes below ten gallons, there are a number of problems that crop up. The most significant of these is that the water volume simply is not large enough to dilute the fish's waste so the filter can process the waste without harming the fish. This is the key factor contributing to the very high maintenance these small tanks require.

The next issue with these tiny aquariums is the risk of sudden chemical changes in the water. Even small amounts of pollutant or impurity can cause devastating changes in the water chemistry. Again, due to the increase in water volume, tanks above ten gallons deal with this much better than their tiny cousins.

Another problem with these tiny tanks is sudden changes in temperature. If the tank is not heated, the temperature can drop much more quickly than a larger volume of water. On the other hand, if the tank is heated, minuscule variations in the thermostat on the heater can cause devastating temperature changes. Even an hour without a confirmation that the temperature is correct can allow a lethal rise or drop in temperature if the heater doesn't quite turn on soon enough, or doesn't switch off right away. Even the residual heat in the ballast of the heater can cause a tiny tank to overheat even when the heater does turn off correctly.

Then, as noted above, at ten gallons, you finally start to get enough water volume that you can have an interesting, and healthy, population of fish in the fish tank.

Remember, fish tanks under ten gallons in total aquarium volume really should be left to only the very advanced aquarium keepers, who understand the risks involved in such a small fish tank, who have a lot of experienced caring for fish and aquariums, who are ready for the additional challenge that a tiny fish tank represents, and who are not concerned about the cruelty inherent in very small aquariums.

"I just wanted to thank you for the information! Your explanation and through answer really helped us save the rest of our goldfish colony - we seem to be back in business in regards to everyone's health."
June 5, 2015
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"Great site, its been really helpful for me! ... Thanks so much for the info, I'm really dedicated to keeping these boys happy and healthy and your information and advice is invaluable. I appreciate your help."
May 30, 2003
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