Best Fish for a 20-Gallon Tank

Aquariums are more than a decorative piece that people put up for aesthetic purposes. They do lend a fresh and personal touch whether in a private living room or a commercial building.



But before they can take their place as the center of attention, careful planning is essential. And not just in terms of gear and equipment for the tank, careful planning and consideration of the would-be dwellers is crucial. After all, it is not an aquarium if there are no fish in there is it?

Aquariums come in all different types and capacities. Having proper knowledge of the fish species that will flourish in a particular aquarium will decide whether the endeavor is a success or a fail. Most people forget that an aquarium is an ecosystem, albeit an artificial one. The habitat of every organism in an ecosystem determines its longevity, productivity, and life. Therefore, having a clear, if not thorough, understanding of which fish species to select for your 20-gallon aquarium is a must.

In this article, we have selected the fish species you should consider for a 20-gallon
aquarium.

1. Neon tetras.

The scientific name of this fish is Paracheirodon innesi. It is a very calm and peaceful fish that does well in a small environment. They can grow up to 1.6 inches but has a surprisingly long life of about ten years. Neon tetras along with other tetras are exceptionally colorful and can thrive in temperatures up to 25 degrees Celsius making the 20-gallon tank a perfect home for it.

These iridescent fishes are also quite playful, and so they appreciate the right amount of hiding places in the form of aquatic plants. Neon tetras can live well in medium lights to low light and are unarguably one of the easiest species to care for. These agile stunners are shallow dwellers and are best kept in numbers of five to six fishes. However, neon tetras, as well as others from the tetra family, can be very sensitive to sudden changes in water, whether in terms of temperature or salinity. Their preferred water with a slightly acidic pH.

2. Zebra Danio.

Its scientific name is Danio rerio, and it is commonly known as zebra fish, due to the olive brown and white striped along the length of its body. They are cheap and also very easy to keep. The adults can reach up to a maximum of 2.5 inches in length and have a lifespan of three to five years. The pH of the water they flourish is neutral.

These are omnivores that like to nibble on the long fins of other occupants in the aquarium. They are relatively peaceful, but they love to swim fast which necessitates the top to be covered by a lid.

Zebra fish thrives in groups of five to six and can adjust well with temperatures up to 24 degrees Celsius and medium lighting. Because of the prominent streaks on their body, they make a stunning view against a dark substrate and plenty of vegetation.

3. Swordtail fish.

The scientific name is Xiphophorus hellerii, and this beautiful fish comes in a lot of varieties. They can live in temperatures up to 25 degrees Celsius and have a relatively short lifespan of three to six years in an exceptional environment. They can grow up to 6.5 inches in length which is a good length for an aquarium fish. They like to swim fast in waters that are slightly alkaline. Males of this species are known to be very territorial, and therefore hobbyists are always advised to keep them in a ratio of 1 male to 3 males.

Feeding bloodworms to these fishes are known to enhance their bright, beautiful colors. An interesting character about this fish is that it gives birth to babies instead of eggs, which has been a fascination to many aquarium enthusiasts.

4. Guppies.

Its scientific name is Poecilia reticulata. They are peaceful and one of the easiest to care for, which has made it a favorite of aquarium lovers. They grow up to 2.5 inches in length and have a lifespan of two years.

Guppies come in a variety of colors and tail shapes and prefer slightly acidic water. They are a schooling species and so should be kept in groups of five to six. Because of their relatively calm and friendly nature, they tend to get preyed on by other big fishes, if they are kept in the same tank. They like exploring the dark and shady bottoms, especially the females during the time of birth.

5. Platy.

The scientific name is Xiphophorus maculatus and a favorite among the aquarium lovers due to its relaxed nature and low maintenance. Adult female platies can grow up to 2.3 inches while males grow up to 1.5 inches and they come in a variety of colors for both sexes.

They prefer water that is neutral to slightly alkaline in temperatures around 26 degrees Celsius. Platies are very friendly but are very active, and they need the right amount of space for swimming.

6. Molly fish.

Its scientific name is Poecilia schenops, and these beauties are a favorite among aquarium enthusiasts for their calm nature and cute appearance. Adult males grow up to 3.2 inches in length and females can grow up to 4.8 inches their life span is a maximum of 5 years.

Mollies come in a lot of various colors, and they are also capable of interbreeding between different colors, which results in a different colored offspring. They do very well in groups of five to six and are quite friendly. They like their water when it is alkaline and having a place to hide among the water plants.

They prefer warmer temperatures of about 26-27 degrees Celsius and are very sensitive to fluctuations in the water, especially if it drops below 25 degrees Celsius.

Final Thoughts

Other possibilities for 20-gallon tanks include dwarf gourami, tiger barbs, bristle nose catfish and Cory catfish. The important thing is that you take into consideration the fish's temperament, the size of the fish after maturity and its social behavior. With a little bit of research and some help from the fish store clerk, you should be able to keep and maintain a 20-gallon aquarium very successfully.