Commissioner Adam H. Putnam

Florida Agriculture: 500 Years in the Making

Aquarium Fish

Frequently Asked Questions

  1. Do I need to remove fish while cleaning the tank?
    No, fish should remain in the tank as much as possible. It is healthier for fish to be moved around as little as possible. They generally move away from the hose when using a gravel vacuum, but it's a good idea to watch to ensure you don't place the vacuum over a fish.
  2. Is it necessary to empty all the water in the tank during cleaning?
    Do not ever empty the tank. You can empty 25-30 percent of the water.
  3. Why does my water look green?
    Algae exists in all aquariums and is a natural occurrence. If it gets out of hand though, the water will begin to turn green. This generally happens when there are too many nutrients in the water, or the aquarium is being exposed to too much sunlight. An overcrowded tank or over fertilizing will cause too many nutrients. Cleaning the tank with a gravel vacuum and wiping the glass with an algae scrubber purchased from your pet store may take care of the job. Two common preventative measures is adding plants to your aquarium and adding one of several types of fish that feed on algae. Your pet store retailer can guide you on types of fish that eat algae.
  4. Do I add the fish as soon as my aquarium is set up?
    You should let the aquarium run for at least 24 hours before adding any fish. The most healthy way to add fish is to put one-fourth to one-third of the total amount of fish you plan to have in your tank, then, add the remainder over the next four to six weeks.

    It is recommended that you float your new bag of fish in your aquarium for approximately 20 minutes. This will allow your new fish to acclimate to the aquarium's temperature.
  5. Is there a limit on how many fish you can have in an aquarium?
    Yes, having too many fish can cause an unhealthy environment and sick fish. It is generally recommended to have a maximum of one inch of fish per gallon of water. This measurement does not include the tail, but refers to the "adult" size of the fish. Your pet store should be able to advise you on how many fish you tank can support and adult sizes of the fish you select.

    Keep in mind that most of the fish you buy have not reached their adult size and a 20-gallon tank (or substitute the size of tank you have) does not have 20 gallons of water in it after you add gravel and decorative objects.
  6. Why is the water in my new tank cloudy?
    This is normal when an aquarium is first setup. It is referred to as a bacteria bloom. The cloudiness should be gone anywhere from two days to a couple of weeks. You can do a 10-15 percent partial water change and gravel vacuuming after a week to speed it up.

    Some hobbyist like to speed up the cycle in a new aquarium by mixing a couple handfuls of gravel from an established tank with the new gravel. The recycled gravel will have "good bacteria" on it to jumpstart the normal cycle that occurs when a new aquarium is set up. If you don't have access to recycled gravel from an existing tank ask your pet store if they will swap some of your new gravel for some recycled gravel out of one of their tanks.

    Live plants are also helpful as their leaves are coated with helpful bacteria.
  7. What kind of tank should I get?
    Size is matter of choice. Important things to consider before your purchase a tank are: how much room do I have; what do I want esthetically; the weight (water weighs about 8 lbs/gallon) of the aquarium in relations to what will support it; and how many fish do I want.
  8. Why do I need a heater?
    Most aquarium fish are tropical fish -- they come from warm climates and warm waters. To keep them healthy we need to provide a warm water environment. A heater made for aquariums is how we insure the correct water temperature. Tropical fish prefer temperatures of 75-78 degrees F. The aquarium heater will cycle on and off automatically. Your pet store can assist you with the size and style to meet your needs.
  9. How do I know if the temperature is correct?
    You can buy an inexpensive thermometer at your pet store. A popular style is flat and sticks to the side of the tank.
  10. What type of filter do I need?
    The filter system is very important for maintaining a healthy environment in your aquarium. You need to make sure you have a "complete" filter system. The system should include a filter or combination of filters, that perform these three functions:

    -- Mechanical: Traps particles and strains and removes debris. It is important that this filter be cleaned or replaced once a month.

    -- Chemical: Removes dissolved substances. Most chemical filters contain activated carbon and often they are incorporated within your mechanical filter. It should be changed monthly.

    -- Biological: Converts ammonia (excreted by fish) to nitrites which in turn are converted to nitrates by bacteria. All filters perform some biological filtration. The larger the surface area of the filter the better. Underground filters are popular. Filters that hang on the side of the tank also perform this type filtration. The underground filter should be cleaned monthly or it will become clogged and not work properly. Your monthly partial water change and gravel vacuum will clean the underground filter.

    Outside filter size: The rule of thumb is that the water flow should be 5-7 times the volume of the aquarium.

    Remember: Filters do not replace the need for partial water changes.
  11. Fun Fish Facts
    Freshwater fish owners maintain an average of 13 fish.

    Nearly one in eight U.S. households keep fish as pets.

    Aquarium fish are the most popular pet in America, with nearly 12 million households owning more than 158 million fish.

    Research and experimental evidence indicates fish aquariums lower blood pressure in both hypertensive and normal subjects.

    There is extensive medical evidence indicating that aquariums are a highly effective means of alleviating stress even in difficult situations such as dental surgery.

    Unlike other relaxation techniques, attending to a fish tank is a spontaneously initiated activity. The brain is programmed to attend to water and the movement of fish, therefore no training or practice is necessary to experience stress reduction.

    Students who are fish owners score the highest on both math and verbal SATs, with a combined score 200 points higher than non-pet owners.

    High-schoolers who keep fish or other pets have an average GPA of 3.5, versus non-pet owners at 3.2.

    Fish keeping began with the Sumerians more than 4,500 years ago.

    The first display aquarium opened in 1853 at Regent's Park in London.

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