Freshwater Aquarium Fish Tanks

The following will be a discussion on the importance of the size of the fish tank and the common materials used in freshwater fish tanks. We will discuss nano aquariums briefly, but for an in-depth look at the pros and cons of nano aquariums and their stocking levels, please refer to my nano aquarium page.

Aquarium fish tank size

The size of the aquarium fish tank is going to dictate many factors of your aquarium hobby.

  • The type of fish that can stock the tank – A small tank might not be suitable fish that grow to a larger size such as goldfish, some cichlids or arowanas.
  • How many fish can you stock the aquarium tank with – A smaller tank that holds less water will be able to support less fish. A general rule in the aquarium hobby is one inch of fish per gallon of water. (Warning: This is an incredibly general rule which is easier followed with smaller fish, a two inch long fish will produce much more waste than two one inch long fish and the waste production grows exponentially from there. Furthermore, certain types of fish produce more waste than others. For example goldfish) Please check out the aquarium stocking calculator which tries to provide a better picture for stocking your tank.
  • A larger tank will provide you more leeway when it comes to water changes and will greater dilute any poisonous ammonia and nitrites that could harm your fish. This will provide you more time to notice and correct any water chemistry issues.
  • The type of lighting, filter, and heating you will require – Filters and heaters are rated based on the number of gallons they can handle. Aquarium lighting comes in different sizes depending on the size of the tank.
  • Where you can place your aquarium fish tank – A gallon of water weighs roughly eight pounds. This means that a 55 gallon tank is going to weigh roughly 440 pounds, which is some serious weight. Make sure your floor is able to support the size of tank you are purchasing, in some cases if the tank is too large you may have to situate it in the basement.

Above are many factors to take into consideration when purchasing a fish tank. The most important factor is probably going to be what you are stocking your tank with. For example, if you want to keep discus, you will need a larger tank as each discus requires roughly 10 gallons of water. Furthermore, discus like to be kept in groups which probably means at least a 75 gallon tank.

Tank materials

Aquarium fish tanks can be created from a bunch of different materials. The following will be a list of the common materials with their pros and cons.


Glass is the most common material used to create fish tanks because it is more cost-efficient than acrylic. (This benefit disappears when you’re dealing with large tanks)


  • Regular aquarium glass takes more pressure to scratch then acrylic or low iron glass
  • Glass tanks depend to be less expensive than the alternatives


  • You can’t do anything about scratches. If the glass is scratched there is no way to buffer out any scratches like you can do in acrylic tanks. You don’t need to be as careful as cleaning an acrylic or low iron tank but you still want to ensure you don’t have a piece of sand or rock between your cleaning pad and the glass
  • A glass aquarium is going to be 4 to 10 times heavier than an acrylic aquarium of the same size. Reason for the difference of the weight factor is due to the thickness of the acrylic you will require depending on the size of the fish tank
  • A sharp impact can shatter one side of the tank, leaving it ruined
  • Glass has a different refraction index than water, which means what you see through the glass is going to be slightly skewed

Conclusion – Should I get a glass tank

Glass tanks have been the norm for over a hundred years, a lot of the cons described will affect you more if you are into aquascaping or aquarium photography. If you plan on taking pictures of your aquarium, due to the refraction issue, your pictures are not going to turn out as good as if you purchased an acrylic or low-iron tank. Now, whether that going to justify obtaining a more expensive tank is also going to depend on the pros and cons of the other tank materials. Let’s check out Acrylic tanks next.



  • Great clarity – The refraction index of acrylic is much closer to that of water, reduces distortion when viewing through acrylic
  • Stronger than glass – Damage that may cause a glass tank to shatter will probably not break an acrylic tank
  • Scratches can be buffered out of the acrylic


  • Expensive – More expensive than regular glass tanks but the added cost disappears with larger tanks
  • Scratches easier than regular glass aquariums – Acrylic is softer than glass which leads to it scratching easier. Be sure to take greater care when cleaning an acrylic tank and use only scrapers that are recommended for acrylic tanks
  • Probably have to build a tank yourself or purchase online


Acrylic tanks are not common in many pet stores or aquarium shops. If you want to obtain one, you’ll likely have to build it yourself or purchase it online. Although acrylic scratches easier compared to glass, the scratches can eventually be buffed out of the tank meaning an acrylic tank should last you a long time. Furthermore, as long as you take the proper precautions, scratches should be kept to a minimum.

 Low Iron Glass

Also called starphire glass, these tanks are all the rage for the planted aquarium and aquascaping enthusiast.


  • Better clarity than regular aquarium glass – starphire glass has a clearer tint compared to the green tint in regular aquarium glass. Refraction index is closer to water than regular aquarium glass making your view less distorted


  • more expensive than regular glass tanks
  • scratches easier than regular glass tank – the removal of the iron makes the glass softer


The ideal aquarist that is going to want a starphire tank is someone that is focused on aquascaping a smaller sized tank. When tanks are smaller, acrylic will end up being more expensive, and small starphire tanks are readily available. The most popular brand in recent years has been Aqua Design Amano (ADA), but there have been several suppliers coming out with lower costing starphire tanks.


If you are just starting out with the hobby, there is nothing wrong with purchasing a regular glass tank aquarium. Especially if you aren’t sure that you will stick with the hobby. If you know exactly what you’re trying to accomplish and you know you’re going to want an acrylic or starphire tank, I recommend getting the tank you want. Often time people try to save money and end up costing themselves way more in the end.

So to sum things up, if you’re unsure what you want, a normal glass tank is going to be the way to go. If you’re the type that needs the best or are very particular about certain aspects of your tank, I’d recommend spending a few extra dollars and getting the tank you want.