Top Freshwater Fish for Beginners

Sean Perry, DVM
By Sean Perry, DVM on Nov. 10, 2022
Fish in tank

A beginner is able to learn the basics on how to take care of an aquarium with a variety of different  beginner fish species. Numerous fish species such as celestial peal danios, golden dwarf barbs, neon tetras, pygmy Corydoras, guppies, betta fish, and dwarf gourami are great beginner species.

Small fish tanks are one of the best ways to get into the hobby of keeping freshwater fish. Small freshwater aquariums can be rewarding and provide entertainment for hours when properly kept.

Best Freshwater Fish Species

Celestial Peal Danios

Celestial peal danios are a small, dark blue fish that have either white, yellow, or tan dots over their bodies. Their appearance is sometimes associated with a galaxy, so that is why they are called celestial.

Males and females can be differentiated by their size and color. Males are thinner, brighter, and have a red stripe that runs through the middle of the fish. Males also have a red belly. Females aren't as brightly colored and their fins are orange to translucent.

These fish like to live in small areas where they can hide within rocks and plants in groups of 10 or more.  It's important to keep more females than males because males can become aggressive.

Golden Dwarf Barbs

Golden dwarf barbs are small golden fish that have faded black banding. The fish max out at about 1.5 inches as adults and can live 2-3 years. Golden dwarf barbs can be great additions to small tanks as this species is docile and can live with multiple fish species.

Males tend to be skinnier than females. Because this species does school, it is best to keep multiple of them together.

Neon Tetras

Neon tetras are vibrant small fish from South America that have blue, red, and white coloration throughout their bodies. They are considered neon because of this bright coloration and their red strip that passes through only half of the body.

Neon tetras max out in size at 1-1.5 inches and are a schooling fish, so keeping multiple fish is recommended. They can live anywhere between 5-10 years of age when kept in appropriate conditions.

Pygmy Corydoras

Pygmy Corydoras are small, silver and black catfish that are ideal for small aquariums. They are one of the smallest fish for small aquariums and are ideal for these environments. These fish are peaceful and can live with other species. Males of this species are smaller than females and both sexes max out a 1 inch in length.

This species searches for food on the bottom of the habitat, often sifting through the substrate with their barbells. A 10 gallon tank can hold up to 8 individuals of this species. Pygmy Corydoras should also be housed with smaller fish species so they do not accidently get consumed by tankmates.


Guppies are fantastic beginner fish. Guppies are a small fish that doesn’t reach larger than 2 inches in size. They can have exquisitely designed tails making them beautiful display fish.

Guppies are viviparous (live-bearing) and breed readily in captivity. If you are interested in breeding these fish, then you should have 1 male for every 2-3 females.

Guppies can be housed as a single species and make a beautiful tank, or they can be housed with neon tetras or Pygmy Corydoras. Guppies should not be housed with any aggressive fish species.

Betta Fish

Betta fish can be great beginner pets for a small aquarium such as a 10-gallon aquarium. This species of fish is aggressive. Males of this species should be house alone, while females can be housed in sororities.

Dwarf Gourami

Dwarf gourami are a beautiful small red fish with blue vertical striping and make for a vibrant addition to a small tank. Many different color patterns do exist. Of all fish mentioned they are the largest—ranging in size from 3.5-4.5 inches.

Dwarf gourami are a docile fish species that mainly likes to live in the upper portion of the water column. This species can live with other fish species as they are not aggressive.

Since they are a larger fish, they do require more space. For a 10-gallon tank, you can safely house about 3 dwarf gourami together. When mixing species, one or two will work well with other non-aggressive species.

Small Fish Tank Tips

Cleaning a fish tank is a must. The smaller the fish tank, the more often it needs to be cleaned. Over time, toxic nutrients build up within the water and need to be removed from the system. Biological, mechanical, and chemical filtration are all needed but are often not enough.

Beginning a routine cleaning and maintenance schedule is recommended. This should include water changes weekly (about 10-20% of the water) and gravel vacuuming the substrate. These are two easy ways to remove waste products from the fish and leftover food items.

A good rule of thumb that helps you determine how many fish can be safely housed in a fish tank is about 1 fish per every gallon. However, this depends on the size of the fish, how often the fish are eating, the filtration, and the water chemistry of the tank. Water chemistry can be more volatile and influenced easier in smaller tanks compared to larger tanks.

In a small 10-gallon tank you should house 6-8 fish, depending on fish size. Many filters are available can be used for small tanks and provide enough mechanical filtration to ensure healthy water for your fish. Small canister filters can be used for an all-in-one filtration system. Under gravel filters can also be used in these small aquariums. Hang on filtration systems are also commonly used for small tanks. Depending on the size of your tank and how many fish are within the tank, it may be a good idea to place a larger filter than your total volume of water. Overfeeding small tanks can happen easily. It's important to not overfeed your small tank because you can easily alter the water chemistry and the water can become toxic to the fish.

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Sean Perry, DVM


Sean Perry, DVM


Dr. Sean Perry completed his undergraduate degree at the University of California, Santa Cruz, earning a Bachelor of Science in...

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