By Eric Crouch, Aqualand Fish Consultant
Misc Frogs II
Misc Frogs III
Misc Frogs IV
Misc Frogs V
Pet World Visit
Here's a gallon jar kept by a true fish keeper. It actually works. Most do not.
You’ve seen them in novelty shops, in offices, in all sorts of places – those cute little desktop aquariums that hold one or two gallons of water – even those that hold up to four.
Some are shaped like gumball machines, some are cylindrical; most are hexagonal. The idea is to have a cute little tank on your office desk, or in the den at home, without going to a lot of trouble.
Mini-tanks almost always are sold as a package – tank, top, light, air pump, filter (almost the works). That’s part of their appeal. They’re compact, cute, cheap, and ready to set up with minimal work. Just add water and fish.
What the instructions that come with such tanks don’t tell you, however, is that there is much more to them than this minimum of work.
Perhaps you already own one of these little tanks. If so, we’ll try to tell you how best to take care of the fish you keep in it.
If you don’t already own a mini-tank, however, the best advice we can give you before you buy it is: Don’t. That’s right. Don’t buy it. It is a lot more trouble than it looks, and it is an effective little death-trap for your fish unless you dedicate yourself to maintaining it just right.
These are several problems with mini-tanks. For example, they come with a filter, but this is small provision for keeping their water clean. An under gravel filter (which is what most mini-tanks come with) is the best type of filter, but for a mini-tank, it is just inadequate.
Under gravel filters use bacteria to break down wastes (particularly ammonia, the main component of fish urine and a major by-product of decomposition of uneaten food) into harmless substances.
As long as oxygenated water flows through the gravel, the bacteria thrive and convert wastes. Problem: a mini-tank is so small that there is no excess water to act as a cushion as ammonia initially builds up. The filter needs time to establish the bacteria. This usually takes at least a couple of weeks -- more likely six.
In a larger tank (say, a 10-gallon tank), there is more of a cushion between the fish and ammonia buildup (simply because there is more water) than in a mini-tank.
Further, a mini-tank is much more easily overcrowded than a larger one. This results in a waste overload on the very small filter.
Another problem: it is nearly impossible to regulate their temperature. First of all, few manufacturers market an affordable aquarium heater that small. Second, a tank so small is highly susceptible to rapid temperature changes. Such rapid raising or lowering of temperature decreases your fishes’ resistance to diseases such as ich.
Finally, most mini-tanks come with an incandescent light fixture. On such small tanks, to use that light for more than, say ½ to1 hour at a time raises the temperature a few degrees. When you turn it off, the temperature drops just as rapidly.
Theoretically, you could heat the tank constantly with the light bulb, but it still responds to temperature changes around it (no thermostat to tell the bulb when to heat up/cool off a bit). It also throws off the internal clock that every fish has in response to the normal night/day cycle.
Most tropical fishes do best at temperatures of 76o to 82o F. Goldfish do best at temperatures of 65o to 74o F. With a mini-tank, tropical temperatures are simply not possible to regulate and maintain unless the tank is placed in a room with a warm, stable, temperature.
Goldfish, on the other hand, can handle a cooler room just fine – as long as the temperature remains constant. Office environments in which the temperature drops several degrees after personnel go home for the day just will not do.
If you have a mini-tank, find a place to put it where the temperature will be constant. Don’t expose it to temperature shifts of even two degrees. The tank’s small size assures that the temperature within will shift correspondingly – and swiftly.
When you set the tank up, be prepared to change about ¼ of the water every other day or so for the first couple weeks until the filter has established the bacteria you need. Ask us about how bacteria cultures can speed up the process. Keep a good supply of water on hand that has been allowed to age for at least 48 hours.
We recommend a mini-gravel vacuum cleaner to make water changes easier. It siphons out feces and uneaten food along with the discarded water. After the bacteria are established, we still recommend at least twice-weekly 25% water changes (as opposed to the once-weekly changes we recommend for larger tanks).
Small goldfish and paradise fish are the best inhabitants available for mini-tanks. One goldfish per gallon is the maximum crowding we recommend. If you really have a hankering for tropicals, and you are certain that you can maintain a stable temperature in the desired range, a betta is one of the hardiest residents of the mini-tank.
You can get away with two fish per gallon with tropicals, so you might try adding a small catfish, one or two small angelfish, or pygmy Gouramis. Or a school of up to five or six small neons or glowlights, and a catfish will do okay. Since they are small, most tetras can be crowded more than other tropicals if you take proper care of them.
Or select a couple of small blue or gold Gouramis or one paradise fish combined with a small catfish for an interesting display.
Guppies (common guppies, not the fancier-finned, more delicate varieties) are a possibility. Forget the algae eater, unless you place the tank near a strong light source such as a window. If you have algae problems in a mini-tank, you are using the tank light too much and screwing up the temperature.
Recognize that if you take proper care of your fish, you will be exchanging them every few months for smaller specimens, for they will soon outgrow their tiny home. IF they are given proper care.
Seem like a lot of work? You’re right. It is. This is why we don’t recommend mini-tanks. Though they are easier to set up and move than larger tanks, they are much harder to take proper care of.
We cannot recommend any tank smaller than a 10-gallon aquarium. They are indeed larger and more work to set up and move, but heaters are available for them. And, even if you don’t heat them, their temperature will fluctuate much more slowly, making them good tanks for goldfish. Mini-tanks can’t be easily lit without throwing off the temperature. Tens are harder to poison with ammonia. Best of all you can put several more fish in a 10 with little trouble.
All of this adds up to less work for you in the long run. After all, the purpose of buying aquarium fish is to enjoy them, right? It is more likely that you will enjoy them if they are healthy and if you don’t have to go to too much trouble to keep them that way, right?
Finally, if you keep fish in a mini-tank, one more important thing should be kept in mind: nutrition.
Make sure you feed no more than they can completely consume in three to five minutes. And make sure that some of this reaches any catfish you may have in the tank, so that it doesn’t starve to death. Feed your fish a food that has about a 3:1 protein to fat ratio to increase digestion and leave less waste AND that lists vitamin and mineral supplements on the label. Feed twice daily.
To mini-tanks, we can only say, “They’re really a hard tank to keep your fish in.” Good Luck. EC.
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