Selecting aquarium fishes

Level: Beginner


Never keep a common goldfish (or other large growing fish) in a small aquarium or bowl. This stunts their growth and puts them at risk. Healthy goldfish can live 10 to over 40 years old and grow to between 12 and 15 inches long. A mature goldfish is not healthy if it is small. It needs a larger tank (55+ gallons).

How to pick the most suitable aquarium fish for your budget

Your budget may define the type of fish you buy. While many people would probably love to keep large beautiful fish like Discus, African Cichlids, Plecostomus or Goldfish, these fish become very large, may be aggressive and can be costly to keep.

An important tip, is to create a budget for your aquarium/fishkeeping hobby. Decide how much you are willing to spend. Not only the initial cost, but also, the ongoing maintenance expenses. Then price out what you will need, to determine what you can afford. This will help you figure out what size tank to keep and therefore, which fish you should buy.

Below, are a wide variety of fishes based on tank size.

Selecting fish based on available space and maintenance

Maybe money is not an issue. If so, you are privileged with the ability to select any tank size. But, perhaps you don’t want an aquarium that takes up an entire room or the work that may come with it. After budget, the next considerations are space and maintenance.

When considering larger aquariums, there are many technologies available which can automate much, if not all, of the maintenance requirements of your aquarium. There are innumerable do-it-yourself options that can simplify the workload of keeping fish. But, space is finite. If you live in a smaller apartment you may want to consider a smaller aquarium. Whereas, if you have a large home, you may have space to dedicate an entire room to keeping fish. Regardless of your situation, realistically consider how much room you have to keep fish and how much of it you want to dedicate to housing aquariums.

It is also critical that you ensure the fish you select are compatible to be kept together.

So, what fishes can be kept in smaller aquariums?

If you are on a tight budget or don’t want to take up a lot of space, consider these fish, for a 5 to 20 gallon aquarium:

  • One Betta
  • One Dwarf Gourami
  • Guppies
  • Small Minnows
  • Ricefish
  • Swordtails
  • Goodeids
  • Mollies
  • Platies
  • Danios
  • Rasboras
  • Killifish
  • Small Barbs
  • Dwarf rainbowfish
  • Pygmy corydoras
  • Pea puffers
  • Small Tetras

What types of fish can be kept in a medium aquarium?

A medium aquarium from 30 to 75 gallons can expand your fish options quite a bit. Also, larger aquariums are easier to keep, because the water parameters do not fluctuate as much as in a smaller aquarium.

In addition to all of the fish noted above, the following types of fish can be great additions to a medium tank:

  • Angelfish
  • Small Cichlids
  • Corydoras
  • Gouramis
  • Barbs
  • Tetras
  • Medium Rainbowfish
  • Smaller Loaches
  • Smaller Plecostomus
  • Smaller catfishes

What types of fish can be kept in large to extra-large aquariums?

If you are familiar with fishkeeping, have adequate budget and time for maintenance, you can get into keeping some super cool fish in a 90 to 300+ gallon aquarium:

  • Goldfish
  • Discus
  • African Cichlids
  • Large Loaches
  • Catfish
  • Rainbowfish
  • Plecostomus
  • Stingrays
  • Arowana

Here is a great resource to use when trying to identify fish compatibility and how many fish to keep in your aquarium:

Do you have fishkeeping questions or additions to the list above?
Comment below!

Leave a Reply

Your email address will not be published. Required fields are marked *