Technology in the aquarium hobby and the way we think about our aquariums continues to evolve. Decades ago, an undergravel filter was the only way to filter an aquarium, saltwater was collected from the ocean and keeping coral in a closed environment was almost unheard of. As times and technology have evolved, a lot of information in the hobby has been misinterpreted or misrepresented. Misinformation passed from hobbyist to hobbyist is often distorted and confused as fact. With so many sources of information available today, it's no wonder myths are formed and spread. We are going to set the record straight on 10 of the most frequently heard aquarium myths so you can bust them the next time one of these topics comes up on your favorite aquarium message board.

1. A fish will eat itself to death.

This is a myth often attributed to Goldfish. Some people actually believe a fish will eat itself to death in a single feeding. But don't start dumping a bunch of food into your tank—overfeeding can affect the health of your fish in other ways. Intestinal blockages are possible if a fish is overfed, as is obesity, which can put excess stress and pressure on a fish's organs. Unconsumed food poses another risk as it will break down in the water, increasing ammonia and nitrites in the short run and nitrates in the long run. Higher waste in the aquarium would prove to be a bigger risk to the fish than having a larger lunch.

Different fish have different feeding requirements. If you worry about over feeding your aquarium you might consider using pre-proportioned foods or an automatic aquarium feeder. This can allow you to feed smaller meals more frequently, which is more natural than one or two large feedings.

2. A fish will only grow as large as the aquarium it's kept in.

This seems to be a common myth among new hobbyists. It's a tragic misstep that can lead to a fed up ex-hobbyist and injured deformed, stressed or dead fish.

In a sense, there is some validity to the theory that a fish will grow to the size of its tank, but in a tragic way. Fish produce an enzyme that when built up in high enough quantities will tell them to stop growing. The interruption of growth leads to health issues, deformities and even death. Insufficient water changes allows the level of this enzyme to build up causing fish to stop growing and, at the same time, a lack of water changes leads to poor water quality which is even more detrimental to the fish. If water changes are preformed regularly, the enzyme level will not build up in the water and fish will continue to grow.

Other considerations in regards to size when selecting a fish include temperament and compatibility with other fish. A larger fish may be more aggressive toward tank mates, especially as it grows. Larger fish can also become stressed, causing them to leap out of the aquarium. Be sure to research any potential new tank additions.

3. Small aquariums are recommended for beginners and are easier to maintain.

Smaller aquariums, such as "nano" and "pico" style aquariums, have increased in popularity in recent years. Often times, a new hobbyist will purchase a smaller tank because they are more affordable and the perceived notion is that a smaller aquarium will be less work.

While nano and pico aquariums can be beautiful and rewarding, they are not generally recommended as starter tanks. First, maintaining healthy water parameters is difficult in a small environment. Water parameters can fluctuate quite rapidly: fish waste can accumulate quickly with less good bacteria to break it down naturally. To maintain a healthy environment, one would need to perform more water changes. A larger aquarium will have a larger volume of water, providing more water to dilute waste and ensure stability.

Another reason why smaller aquariums aren't the best choice for beginners is the small size prevents new hobbyists from keeping certain fish or coral. After investing in equipment for a small aquarium, upgrading can be difficult, especially when you consider that much of the equipment will not transfer to a larger aquarium. With a larger aquarium, you can provide room for growth and increase the diversity of fish, coral and invertebrate.

When purchasing a new aquarium, the best advice is to get the largest aquarium you can afford that will fit in the space you have available. We think an aquarium between 29 to 55 gallons would be a great starter size.

4. You don't need a heater-your house is warm enough.

Instinctively, when thinking of aquarium heaters, the idea that comes to mind is of bringing a cold tank up to an appropriate temperature. It is easy to forget about the other job of the heater: maintaining the temperature. While pumpslighting, and ambient temperature may be sufficient to keep temperature warm during the day, temperatures can drop at night as equipment turns off or ambient temperatures drop. Temperature fluctuations are stressful to fish and coral. An aquarium heater prevents drops in temperature and helps maintain the correct temperature at all times.

5. A larger protein skimmer or filtration system will eliminate the need for water changes.

While filtration can help keep water parameters in check, it is not a replacement for water changes. Filtration should be thought of as a means of keeping water parameters in check until your next water change. Filter media and protein skimmers perform tasks that are beneficial to your aquarium, but can't replace water changes for two reasons:

  • Water changes remove waste products, such as nitrates, from the water. Nitrates are the last product of the nitrogen cycle and are not naturally removed from your water.
  • There are many minor trace elements used up in our aquariums and performing water changes replaces them.

6. You should try caring for a freshwater tank before a saltwater tank if you really want to be successful with marine aquaria.

Freshwater aquariums are often assumed to be easier than their saltwater counterparts. While freshwater fish-only aquariums are great and can be mastered fairly easily, some freshwater systems, such as planted freshwater tanks, are arguably more work than a marine-reef aquarium. A simple marine aquarium doesn't have to be difficult or extravagant. Marine fish-only aquariums or FOWLR aquariums (fish only with live rock) are a great way to get introduced into the saltwater side of the hobby. Most of the principles and foundations for aquarium care will be the same for both setups. If one still feels the need to be challenged, a fish-only or FOWLR aquarium can be easily upgraded to a reef system.

Upgrading from a freshwater to saltwater tank often requires additional or different equipment, which may not be compatible. If your heart is set on a marine tank instead of a freshwater aquarium, don't settle for one versus the other: grab a good book, join a forum, and build your dream tank!

7. You need 3 to 5 watts of lighting per gallon for good growth.

The "3 to 5 watts per gallon" rule says coral need three to five watts of lighting per gallon. This myth gained popularity because it provided an easy-to-understand method of selecting lighting. It was a much simpler answer than, "It depends." There are a few reasons why this myth doesn't hold water:

  • First, the rule doesn't account for the height of the aquarium. For example, a 60 gallon cube (24"x24"x24") would require slightly more watts of aquarium lighting than a wider 55 gallon aquarium (48"x12"x21"). In reality, the longer tank would certainly require more lighting based on the length alone.
  • Upgrades and improvements in light technology have changed the way we think about lighting. Modern light measurements are in PAR values (photosynthetically active radiation). A clear rule of watts-to-gallons is impossible when you compare two popular light options: a 250 watt metal halide light and an LED fixture consuming 118 watts. Both would cover the same area and provide similar PAR readings.

8. Don't do water changes while cycling a tank.

This myth says that performing water changes actually extends the time it takes to cycle an aquarium. Water changes are beneficial when cycling an aquarium as they dilute ammonia and nitrite. Reducing the amount of ammonia or nitrites won't slow the cycle down. It is said that removing water also removes beneficial bacteria. Most of the bacteria in an aquarium will reside on the substrate (rockssand and gravel), so removing water will not affect the bacterial load.

9. Your pH must be maintained at exactly 8.3.

A pH of 8.1-8.3 is ideal, but a pH of 7.8 to 8.5 is acceptable. Levels in the acceptable range don't warrant any immediate change. Don't sweat a point or two if it isn't moving much. The key is consistency. If pH tests are consistently 8.1, don't panic. Adding buffers might make the problem worse. Monitor your pH for a week at the same time every day, preferably right before lights out when your pH will be at its highest. If your pH changes frequently, is below the appropriate range of 7.8 to 8.5 or seems to change frequently, take corrective actions. Otherwise, don't sweat it!

10. It takes a month and a half to properly cycle a tank.

An aquarium can be set up and ready for a few fish in as little as one day if setup properly. Adding live rock and a handful of live sand can "seed" the aquarium with the beneficial nitrifying bacteria needed to properly break down waste. The addition of bacterial supplements can introduce and help encourage the growth of beneficial bacteria. Adding live copepods will help add biodiversity to your sandbed and rock. Be sure to stock your aquarium slowly to prevent any ammonia spikes.