How To Properly Set Up and Maintain Fish Aquariums

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Forty years ago when I was a teenager I went to a pet shop with a friend to get some supplies for his pet. That was the first time that I was truly exposed to the world of fish! I had seen goldfish, of course, and the occasional guppy tank but I had never seen the assortment of tropical fish that was available. From that moment on I was hooked and soon became involved in fishkeeping. Unfortunately, back then many pet stores were more interested in selling fish and supplies than in actually teaching how to care and maintain them. I guess it was more profitable to keep selling fish to replace the ones that were lost than to teach someone how to actually care for them. Times have certainly changed for the better and many fish stores are owned by marine biologists or others trained in fishkeeping. But, back in my teens , I had to learn how to maintain fish through trial and error. It wasn’t always easy but in time I learned many things over the years and after a lot of research and experimenting I became pretty adept at maintaining a tropical fish aquarium. Twelve years ago I got involved with saltwater fish and I almost felt like a kid again. It’s a very exciting and satisfying feeling to successfully set up and maintain a miniature ocean right inside your home.

Over the years, I have helped several of my friends set up their aquariums and teach them how to successfully maintain them. Once, a friend suggested that I should think of doing this professionally as a sort of “average guy” type way of explaining the process to others. The following is just that, an explanation of how to set up and successfully maintain a fresh or saltwater aquarium in every day language without a lot of technical and complicated words.

Feel free to print a copy of this for your own personal use!
You may not distribute, sell, or add its contents to websites without the permission of the author.

That Fish Guy Mike/Michael Hyman; takes no liability of wrong doing in regards to the methods in how you set up your tank, what you put in your tank, and what lives or dies in your tank. This e-book is to be used as suggestions only from a regular guy who knows a whole lot about fish through trial and error.
How To Properly Set Up and Maintain Fish Aquariums

Starting Out

If you’ve never kept fish before I suggest that you start out first keeping freshwater ones. The reason for this is simple…money. Fishkeeping can be quite expensive and it would be best to start off on a small scale so that you can determine if this is a hobby you truly want to pursue. Freshwater fish usually are much cheaper than saltwater ones and take less equipment to maintain. I’ve seen people rush out and buy saltwater fish and get so disgusted in their ability to keep them that they give up in a few months after spending a lot of money. It’s best to start simple and then move up the chain, so to speak, as you learn more and become more comfortable with your abilities.

I believe that an aquarium of about twenty gallons is perfect for a beginner. It is not too small for many fish and certainly affordable. Personally, I like 55 gallon tanks or larger when keeping fish but I do not think that anyone should spend that kind of money until they have decided that they really want to spend the time and money that it takes to maintain an aquarium. O.K. let’s say you’ve bought a 20 gallon tank, what next? Well, the tank (and stand) is just the beginning. Now you need lights, filters, gravel, decorations, a heater and maybe even a chiller. Notice that I haven’t mentioned fish? Before buying fish you have lots of other choices and decisions to make. Some of these decisions will be based on the type of fish you wish to keep and how you want to keep them. If you decide that you like a certain type of fish from a certain part of the world then you should set up a tank that duplicates that environment. If that’s the case, everything you buy would be based on that environment. If you decide on having fish from several parts of the world you have to set up your tank so that all of your fish can survive that environment. I’m getting ahead of myself here, talking about fish, so let’s revisit this later and talk more about supplies now.


Let’s discuss lights first. There are basically five types of lighting available; incandescent, fluorescent, compact fluorescent, metal halide and lunar light.

  • Incandescent lighting is basically what is used in your home and can be used in small aquariums. They are quite hot, however, and I feel are not suitable for aquariums.
  • Fluorescent lighting is what is most widely used in aquariums. The bulbs are cool operating, energy efficient and come in a variety of lengths and wattages to fit most aquariums. Fluorescent systems are able to provide sufficient light for plants as well. Most tanks work well with this type of lighting and it’s what I would recommend.
  • Compact fluorescent bulbs are called the “next generation” in fluorescent lighting. They are extremely bright in their output without using a lot of energy and they generate little heat. These lights are affordable and are a good choice for most aquariums. I personally feel that fluorescent or compact fluorescent lighting is the best decision on lighting for the average aquarium.
  • Metal halide lighting is the top of the line for fresh and saltwater aquariums. It produces extremely bright light and it’s great for plants or corals. It is however, expensive and produces a lot of heat. Most metal halide systems contain fans to help cool them but they still generate quite a lot of heat. I use a combination metal halide, fluorescent and lunar light system in my saltwater tanks but I do not recommend these lights for the beginner. They are just too expensive to justify for someone starting out.
  • Lunar lights are fairly new to the trade. Basically, these lights come on at night when your regular lights are off and they mimic moonlight. I find that fish benefit from these lights because it gives them a feeling of normalcy. Many fish feed at night and many also spawn at this time. Having these lights help them maintain a normal lifestyle.

When purchasing lights other considerations should come to mind. A freshwater tank containing plants needs lots of light so you should purchase bulbs that are brighter than say a tank with just fish. Also, in time these bulbs will change the intensity of light they produce. All bulbs produce light in a “spectrum” that plants and fish use to grow just like natural sunlight. Even though you don’t see it these lights slowly change the spectrum of light they put out and in time produce a light that are not beneficial to plants. To keep this from happening you will have to replace the bulb ever so often. Normally fluorescent bulbs should be replaced every six months and metal halide lights should be replaced once a year.

You should know that lighting serves many purposes, besides illuminating the tank it provides the aquarium inhabitants with a natural feeling of night and day. Proper lighting will make fish and plants strong and healthy. Improper lighting can make fish and plants unhealthy and promote unwanted algae. To make my lighting seem more natural I’ve installed timers to my lights that simulate a natural sunrise/sunset environment plus the lunar lights provide them with a natural nighttime environment.

Filtration Systems

Now that you’ve learned about lighting let’s move on the filtration systems. Like lighting there are many types of filters but all filters are either one or a combination of three types of filtration. These types are; mechanical, chemical and biological. Let’s review each type.

  • Mechanical filtration is a very simple form of filtration. A sponge, cartridge or some type of pad is used to trap particles of uneaten food, fish waste or other matter from the aquarium. These filters are simple and need only to be changed periodically when dirty.
  • Chemical filtration is found in all types of water systems. Many homeowners use chemical filtration on their drinking water or pool systems. This is done by using charcoal or resins to remove waste. Besides removing waste, chemical filters also can eliminate materials that can cause odors and the discoloration of aquarium water. Chemical filtration also removes toxins, ammonia, nitrates, phosphates and many other chemicals that are harmful to fish.
  • Biological filtration is a natural form of filtration. It is one of the most important types of filtration and is very beneficial to fish and plant life. Biological filtrations occurs when beneficial bacteria convert organics (fish waste, uneaten food, etc.) into less toxic compounds that can be then removed by periodically removing the water along with other filtration. Usually, these bacteria occur over time in the aquarium naturally and when material is provided for the bacteria to grow and thrive a biological filter is created.

Now that we know the types of filtration it is up to us to decide on the type of filter we want. There are many types of filters. Some provide only one type of filtration while others will provide all three. Filters that provide only one or two types of filtration can be helped by adding another filter that uses the third type of filtration. Canister, wet/dry filters are an excellent way to provide all three types of filtration. Undergravel filters are nice to have as a helper but should not be used alone. In small tanks submersible filters can also be used. For the beginner I suggest a type of canister filter suitable to the size of your tank along with an undergravel filter. These are great for freshwater systems. They are also good for saltwater systems but wet/dry systems are better I feel when in saltwater.


There are many types of gravel available that come in assorted sizes and colors. For the most part choosing gravel really depends on your taste. You can choose a color that makes your fish stand out or you can choose something that gives a natural look. The choices are just about limitless. One thing you should be aware of, however, is the size of your gravel. Pick your gravel in a medium to large size. Small sized gravel tends to pack tightly in the tank and can cause certain harmful bacteria to grow. Also, having an undergravel filter helps air and water to circulate under the gravel which eliminates “deadspots” and cuts down on harmful bacteria.


For the beginner I suggest a standard heater that attaches to the top of the tank. The size would depend on the size of the aquarium. If you decide later on to really get into the hobby, heaters can be purchased that attach to the bottom of the aquarium (below the gravel) or to an inline system along with external filters. To be honest, these heaters work no better than the cheaper ones the only difference is that they are out of sight.


Many people keeping aquariums don’t even know what a chiller is. Basically, it’s an air conditioner for the water. Fish and plants (especially coral) do not do well in water temperatures above 80 degrees for very long. The oxygen that is in water gets less as water temperatures rise which makes it hard for fish to breathe. Fish become stressed and will stop eating and eventually die. Chillers can be expensive, especially for larger tanks. Fortunately, new technology has brought out chillers for smaller aquariums that are not too expensive. The best way to decide if you need a chiller is to watch your tank’s temperature for about a week during the summer. If the temperature stays above 80 degrees during most of the week then I recommend that your purchase a chiller.


This is where you get to express your desire on what your tank should look like. Some people like a heavily planted tank with few fish. Some like to replicate a particular fish’s environment with deadwood or rocks. Many also buy artificial decorations of many different types. The choices are yours. Make sure, though, that you have given your fish places to hide so that they can get away from more aggressive fish or wait until dark (if they are nocturnal fish). Do not purchase coral as a decoration, however. Besides not being natural for a freshwater tank coral is sharp and can cut fish. Whatever you do use as decoration, make sure that it is clean and does not contain anything that could contaminate your tank. It is best to wash everything you plan to put in your tank with fresh water (no soaps) and then let it sit out in the sun for a few hours.

Testing Equipment

A lot of people feel that they can eliminate this purchase and use the money for something else. This would be a huge mistake. The chemistry of your water is vital to the health of your aquarium. High levels of ammonia, nitrate, nitrites, phosphates, and an incorrect PH will cause all sorts of problems for your aquarium including fish death, algae blooms and cloudy water. Testing equipment is cheap and easy to use and should be used regularly (at least once a month, twice a month for tanks 20 gallons or smaller) to ensure the health of your aquarium.

Setting Up the Aquarium

Now that we have our aquarium, stand, lights and all the other stuff, let’s talk about setting it all up. First you need to decide where to place your aquarium. You will want to put it where you can see it easily. Also, it will have to be near a power source and away from drafts or direct sunlight. Placing an aquarium by a window is not a good idea, for instance, because it will create too much heat and more light than the tank needs. Find a good position that bests suits you and place your aquarium and stand with enough distance away from the wall that you can have access. You will need to get behind your aquarium from time to time so leave yourself enough room. You will also need room for any object (filter, etc) that will hang on the back of your tank so plan ahead. Remember, once your tank is filled with water you cannot move it. Fresh water weighs 6.6 pounds per gallon and the weight of the water alone will break your tank or at least cause a leak if you try to move it with water inside.

After the tank is where you want it start hooking up your filters, heaters and other equipment. When that is done take the gravel that you have purchased out of the bag and pour it into a clean bucket. Rinse the gravel with clean water so that any dust will be washed away. This will help keep your water clear. After rinsing the gravel carefully pour it into the tank and arrange it as you see fit. Once the gravel is in place you can then install your decorations. When this is all done stop and look at what you have accomplished. If you want to make changes now is the time to do so. Once you are satisfied that everything is how you want it you can begin to add water.

Before adding water, however, let’s talk about it. The water that comes from your faucet likely contains chlorine and other additives put in by your water company. Most of these chemicals are highly toxic to fish and will kill them. To get rid of these chemicals you can purchase solutions from your pet store that will eliminate these chemicals. Another solution is to use “reverse osmosis” or deionized water. This type of water is as pure as possible. It can be obtained at water supply stores or maybe your pet store. Reverse osmosis filters or deionizers can also be purchased so that you can filter the water that you have at home. Whatever water you use, try to make it as pure as possible. Once you have your water slowly pour it into your tank without disturbing your gravel, etc. Pouring against the glass usually helps.

With everything installed turn on your filters and see how it all works. Check for leaks, water flow and that all things are working smoothly. I like to let my freshwater tanks run like this for a day or two before adding fish just so that I know that the filters are working and there are no leaks. This also gives material inside the tank time to settle and the filters time to remove dust, etc. It is o.k. to put your plants in at this time if you decide to have them. Hopefully, you have checked on the type of fish you want and you know if they will leave your plants alone. Some fish love plants as a hiding place and plants filter the water for fish just as they filter the air for us. Some fish, however, will eat whatever plants they see and should not be placed in a tank with plants.
Once everything is installed and working you should test the water to see if everything is in the correct levels.

Adding Fish

Hopefully, you have looked around and decided on the type of fish you want. A smart move would be to learn all that you can about the type of fish you choose. Its native waters (chemistry), habitat, aggressiveness, and type of food it eats are all important things to know that will keep your fish alive and happy. Also, aquariums are divided into two types; species and community. A species tank consists of fish of one type. These are appropriate especially if you intend to breed or if the species you want is very aggressive to others. Some fish can be aggressive to its own kind as well so you really need to learn all about the fish you want. Community tanks contain fish of different species that live well together. These tanks can be quite beautiful with fish of different colors swimming at different levels of the tank. The best way to learn about the fish that you are interested in is to buy a book on aquarium fish. Knowledge is power and it is always best to learn everything you can when keeping fish.

After deciding on the type of fish you want you’ll need to decide on the number of fish to buy. You cannot fill your tank with fish and expect them to live. They need an appropriate amount of room to swim and hide. Also, fish waste and uneaten food will produce ammonia in your tank. A large fish population will produce more ammonia than your filters can handle and your fish will not survive. There used to be a rule of thumb that you could have one inch of fish per gallon of water. That has fallen out of favor but it is not a bad way to figure out the number of fish you plan to keep IF you add the size of the fish when it is grown instead of when you buy it (most fish books will list the average size of fish at maturity). It really is better to have too few fish rather than too many. A crowded aquarium will result in stressed and diseased fish and will give you nothing but headaches. Take the time to find out the total size of your fish at maturity and then figure the number of fish to keep.

Now that you’ve decided on the type and number of fish to keep you have to plan on the order of introducing them into the tank. You should first introduce a few hardy fish into the tank to start the chemical cycling process. Once fish are introduced into the aquarium, fish waste and uneaten food will produce ammonia and nitrates. This is highly poisonous to fish. Your filters will remove these chemicals but not soon enough if too many fish have been put in the tank at one time. Once ammonia and nitrates are in the aquarium, beneficial bacteria will form that will break these chemicals down to a less harmful substance. Your filters and waters changes will keep these chemicals down to low or zero levels. Checking these levels regularly with your test kit insures your fish’s health. After you have introduced your “starter fish” and the chemical levels are back to normal you can then begin to add more fish. You should always add just a few fish at a time and constantly check on your water chemistry.

Fish should also be introduced based on their temperament. Aggressive fish should always be introduced last while passive fish should be put in first and given time to get used to their surroundings and find suitable hiding places.

When introducing fish into the aquarium, care should be taken in placing them into the tank. Fish are not tolerant of temperature changes or differences in water chemistry and you cannot just simply drop them from the bag they were placed in at the pet store into your aquarium. It is best to open the bag and let it float in the tank (without letting water pour in) and regularly put a little water from your tank into the bag so that the fish will acclimate to your water and temperature. Doing this for about an hour should be enough. Once you have done this, take the fish from the bag and place it in the aquarium. If the fish seems stressed and you can retrieve it place it back into the bag and continue to slowly add water from your tank. All fish will probably hide when placed in the tank. This is normal. Stressed behavior usually has the fish cornered near the top of the tank breathing rapidly or swimming erratically. Never pour the water from the bag into your aquarium. It is always possible that parasites or disease can exist in the tanks from the pet store and you do not want to introduce that into your tank. I always recommend to people with large aquariums to keep a small quarantine tank so that all fish are kept separate for about a week just to keep diseases and parasites from the main tank. For most people with small tanks, however, this practice is considered too expensive. Still, it is always a good idea to try and keep parasites and diseases from your tank.


You can divide fish eating habits into three categories:

  1. Herbivores eat plant material
  2. Carnivores eat other animals and
  3. Omnivores eat both plants and animals

Basically, food for all three types of fish can be purchased in many forms. You can buy food in flake form, freeze dried, frozen or live. I like to buy food in all three forms so that my fish get a variety of diet and to make sure that they receive all of the nutrients and vitamins possible. I try to mix the foods to make the fish’s life interesting. It is a good idea to feed your fish a small amount several times a day versus a lot at once. Fish have small stomachs and can only eat a small amount at a time. Overfeeding just creates more mess for you to clean up later. Feed your fish only what they can consume in about five minutes.


Keeping your aquarium clean and your fish healthy is a job that has to be done regularly. Always check your tank for uneaten food or other detritus that can pollute your aquarium. Check your water quality and clean your filters on a regular basis. Aquariums of 20 gallons or more should be cleaned about once a month and aquariums of a smaller size should be cleaned about every two weeks. Also, change about 10% of the water at these times. Always use the best water available and try to keep the temperatures close.

Now that you have your fish installed, you only need to sit back and enjoy the serene beauty you have created. There is nothing more relaxing or enjoyable than a properly functioning aquarium. I wish you the best in your venture and if you decide to continue to become more involved in the keeping of fish, please look for my books on more advanced fishkeeping.

Live vs. Fake Aquarium Plants what your choice?

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