The 11 Best Pet Fish to Start Your Freshwater Aquarium

·13-min read

At first glance, a pet fish is a piece of cake. Yes, they are very chill pets compared to dogs and cats, but setting up their environment is where a lot of people flounder (lol!). For this reason, we rounded up the best pet fish based on how intense they are to take care of and how well they play with others. All of the fish on our list are freshwater fish; saltwater tanks are really meant for experienced aquarists. Fear not! Freshwater fish can be as colorful and exciting as exotic saltwater species. Most of the fish on our list are quite social and prefer living in a diverse aquatic community. Like any animal companion, the best pet fish is a happy pet fish.

Fish tank 101

Happy pet fish live in tanks designed specifically for them. This means adhering to certain temperatures, pH levels and hardness ranges. Hardness refers to how saturated the water is with certain minerals. Again, many of the best pet fish are adaptable and can thrive within wider ranges. No matter what, be prepared to spend quality time studying each species you plan to toss in a tank. You’ll need to know the stats so you can keep tabs on their environment.

Speaking of environment, have some fun with it! Many fish enjoy having real plants in their tanks. The goal is to recreate their natural habitats. Not only do plants provide shelter and protection, they help oxygenate the water and filter the tank naturally. However, plants alone are usually not sufficient filters! If your pet fish poops a ton or you have several different species in one habitat, a high-quality water filter is a must.

Substrate is the word used to describe the material on the floor of an aquarium. Sand, pebbles and rocks are all substrate options, though it seems soft sand is preferable to bottom dwellers and fish that enjoy digging. Since many pet fish opt to swim at the mid- and top-levels of the tank, substrate really only affects creatures who get into and near it.

Aquarium Source strongly advises fish tanks with secure, breathable lids. Many fish are jumpers and will accidentally flop out if nothing keeps them in. Water heaters are also a must for home aquariums. Many of the best pet fish—for beginners and experts alike—are from tropical regions and need their water fairly warm.

Finally, it’s best to clean your fish tank once per week. Cleaning doesn’t mean dumping out all the water and refilling it! Instead, Country Vet advises removing about 25 percent of the water in the tank and replacing it with new, treated water. Treated water is just tap water treated with a water conditioner.

Balancing temperature, hardness, pH level and water quality is essential to maintaining a healthy fish tank - and healthy fish. Sudden changes could be lethal to some fish. Plan on checking stats often (once per week, especially right when you set it up) with an aquarium test kit to monitor your mini ecosystem.

Can I put different kinds of fish in one tank?

By following a few guidelines, you can successfully put different kinds of fish in one tank. First, all the species in the tank should have the same environmental requirements. Freshwater and saltwater fish don’t mix, nor do fish who need cooler temps and those from the tropics. Make sure you understand their natural habitats.

Second, confirm the species you purchase get along well with others. Oftentimes males are aggressive with other males within the same species. Some fish, like the Betta, are aggressive in general and may pick on others. Check out where in the tank each species hangs out as this could help them get along swimmingly (lol!).

Livebearers vs. Egg-layers

Some fish lay eggs and babies fly out by the thousands. Others, several of which are on our list, are livebearers. Livebearers have unfertilized eggs inside them and if presented with the opportunity, may mate and give birth to a lot of new fish. If you want to avoid an overcrowded tank, stick to one gender (ideally females, as males tend to get aggressive with each other). Babies often become fish food (even within their own species) if not separated into their own space!

Feeding pet fish

Most of the fish on our list are omnivores, which means they happily gobble down fish food pellets and flakes. High-quality fish food should contain lots of protein. A few fish on our list are herbivores and love greens like spirulina and algae. Almost all fish are going to be thrilled if you treat them to live food like bloodworms (yum!).

Overfeeding is a big problem for pet fish, so don’t get swept away. Some require just one meal a day or several small meals. Typically, you’ll remove any excess food after two minutes so your fish don’t gorge themselves. Feeding time is an excellent chance to observe your fish’s behavior. If they won’t eat or their colors have faded, check on the health of your aquarium.

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1. Betta Fish

Appearance: Variety of colors, long tails
Size: 3 inches
Characteristics: Aggressive
Maintenance: Low
Habitat: 5+ gallon tank
Compatible with: Small, mellow, earth-tone fish like Pygmy Corydoras
Diet: Omnivore
Life Expectancy: 2-5 years
Type: Egg-layer

Betta fish come in spectacular colors. You can literally find them in hues of blue, purple, red, yellow—even neon orange! Though males can be aggressive with other bettas, a single betta can exist peacefully with other fish as long as their tank mates are small, unaggressive and not brightly colored. Madeline Huston at Aquarium Store Depot says bettas are fairly resilient and are “able to sustain themselves in stagnant, oxygen-deficient water systems. They are proven to survive even in less than ideal conditions.” This doesn’t mean ignoring your fish! Clean their tank at least once per week (or invest in a filter) and add a live plant to keep the water oxygenated.

2. Cherry Barb

Appearance: Brown or tan with red or orange highlights
Size: 2 inches
Characteristics: Shy
Maintenance: Low
Habitat: 25+ gallon tank
Compatible with: Other barbs, Neon Tetras
Diet: Omnivore
Life Expectancy: 4-6 years
Type: Egg-layer

Cherry barbs love living together, so plan on getting at least five for a single tank. They’re also pretty shy! It’s best to equip your tank with lots of hiding spots and let cherry barbs get the lay of the land before introducing more fish. Beyond that, these fish are incredibly low maintenance. They eat just about anything and enjoy swimming around their tanks in schools. Even if you don’t decide to breed your cherry barbs, it’s wise to get at least two females for every male to prevent males from overwhelming a single female (or fighting with a male for her attention).

3. Corydoras Catfish

Appearance: Various colors, typically brown and spotted
Size: 1-4 inches
Characteristics: Friendly, calm
Maintenance: Low
Habitat: 10+ gallon tank with 2+ inches of substrate
Compatible with: Corydoras Catfish and peaceful fish like Guppies or Swordtails
Diet: Omnivore
Life Expectancy: Up to 20 years
Type: Egg-layer

Also known as the Cory catfish, these sweet creatures are bottom feeders who enjoy scavenging for their food (definitely buy bottom feeder tablets so they can dig for their meals). Their hobbies include swimming in sync with other Cory catfish and hiding in shady spots. Ideally their tank should have a soft, sandy bottom. Though they have a tough exterior made of bony plates, they are super sensitive to change and have been known to die quickly when transferred from the pet store to home. Be sure water conditions are as close as humanly possible to their former habitat.

4. Fantail Goldfish

Appearance: Round with long tails; orange, white, black or calico
Size: 6-8 inches (this includes the tail!)
Characteristics: Mellow
Maintenance: Low to Moderate
Habitat: 10-20+ gallon tank
Compatible with: Slow, calm fish like Cory Catfish or other goldfish
Diet: Omnivore, ideally live or frozen food
Life Expectancy: 5-10 years
Type: Egg-layer

Goldfish are the quintessential pet fish! There are actually many varieties of goldfish (Oranda, Shubunkin, Comet, Ryukin) but we chose the fantail for its flair. Just look at their lengthy tails and fins. These are dazzling fish with mellow dispositions. Fantail goldfish do well with other calm creatures who can live in cooler water. Though slow-moving, they love to explore, so avoid large pebble substrate which could cut them if they decide to dig around. Crazily enough, fantails don’t exist in the wild; their closest relative is the wild carp. Even more crazy is their ability to produce a lot of poop. Definitely look into quality water filters and be prepared to change at least 25 percent of their tank water weekly.

5. Guppy

Appearance: Variety of colors
Size: 2-3 inches
Characteristics: Social, active
Maintenance: Low
Habitat: 10+ gallon tank
Compatible with: Guppies, Molly Fish, Neon Tetras, Zebra Fish
Diet: Omnivore
Life Expectancy: 2-3 years
Type: Livebearer

Guppies are like bettas without the possibility of aggression. The males are just as colorful—if not more so—and can live peacefully with each other and many other species. Guppies are active livebearers who enjoy swimming around and through tall plant life. The one thing to note about these fish is that females can store sperm in their ovaries…for a while. So be warned if you purchase females only and walk in one day to find a slew of ten to 50 new baby guppies hanging out.

6. Molly Fish

Appearance: Variety of colors, often black or orange
Size: 4 inches
Characteristics: Adaptable, friendly
Maintenance: Moderate
Habitat: 10+ gallon tank
Compatible with: Swordtails, Guppies
Diet: Plants, algae
Life Expectancy: 3-5 years
Type: Livebearer

Molly fish are super popular and there are almost 40 unique species to choose from. While typically very adaptable and easy to care for, there are some varieties (like the Sailfin Molly) that require more meticulous care and larger tanks. Generally though, mollies are hearty and four can live well in a 10-gallon tank with plenty of plants. In the wild, mollies primarily eat plants and algae. In captivity, they’ll probably scarf down pellets or flakes with the other omnivores, but you may want to add spirulina to their diets to keep them healthy.

7. Neon Tetra

Appearance: White with a short red stripe and an iridescent blue stripe
Size: 1.5-2.5 inches
Characteristics: Social, active
Maintenance: Low to Moderate
Habitat: 20+ gallon tank for a school
Compatible with: Neon Tetras, small friendly fish, bottom dwellers
Diet: Omnivore
Life Expectancy: 5-10 years
Type: Schooling, egg-layer

Neon tetras must live with a school of fellow neon tetras! This is why their tank size is so large for such a small fish. Tanks shouldn’t be brightly lit either—give them soft light and plenty of plant life to mimic their natural Amazonian habitat. Like Cory catfish, neon tetras are more sensitive to changes in water. Never plop them into a fresh tank; create an established environment for them before bringing them home. Finally, if you notice their bright neon and red stripes fading in color, get that fish out of the tank immediately. They may have Neon Tetra Disease which is caused by a parasite and could kill off all your fish! As long as you keep water conditions stable, there’s little risk of this happening.

8. Platy Fish

Appearance: Variety of colors, short, stout
Size: 1.5-2.5 inches
Characteristics: Easy-going, playful
Maintenance: Low
Habitat: 10+ gallon tank for small group
Compatible with: Platys, Guppies, Swordtails, Zebra Fish, Mollies, Corydoras Catfish
Diet: Omnivore
Life Expectancy: 3-5 years
Type: Livebearer

Native to Central America, platy fish are playful and adaptable creatures who make great additions to freshwater aquarium communities. These are also ideal fish for anyone who wants a ton of fish without a ton of space. A small school can thrive in a 10-gallon tank with lush plants on either side (keep the center clear so they can dart to and fro). Though they eat anything, like mollies they have a palette for vegetarian meals. Platies do best in groups with more females than males.

9. Silver Angelfish

Appearance: Silver with black stripes
Size: Up to 6 inches
Characteristics: Territorial
Maintenance: Low
Habitat: 30+ gallon tank, soft water
Compatible with: Peaceful medium-sized fish like Neon Tetras, Catfish, Swordtails
Diet: Omnivore
Life Expectancy: 5-10 years
Type: Egg-layer

Silver angelfish are among the most popular angelfish (there are tons of varieties) because of their stunning good looks and low maintenance lifestyle. Originally from South America, these shiny fish enjoy bloodworms and blackworms, but will happily eat fish pellets and plants. Their territorial and predatory instincts mean they might eat smaller fish, so place them with medium- or large-sized pals if you must. Silver angelfish prefer tall tanks to wide ones—and give them plenty of tall seaweed to hide behind.

10. Swordtail

Appearance: Variety of colors, males have long back fin
Size: 4-6 inches"
Characteristics: Adaptable
Maintenance: Low
Habitat: 15+ gallon tank for one fish; 30+ gallon tank for more
Compatible with: Swordtails, Platyfish, Cory Catfish, Angelfish, Neon Tetras
Diet: Omnivore, 2-3 small meals per day
Life Expectancy: 3-5 years
Type: Livebearer

Say hello to a super social fish! Swordtails love company as long as tank mates are not aggressive (they’re too nice to handle confrontation). It’s unwise to keep just one swordtail because they’ll become depressed. When building a fish community, aim for a ratio of four female swordtails for every male to avoid any scuffles. Like guppies, these active fish love tall plants and couldn’t care less about the substrate.

11. Zebra Danios

Appearance: Blue and gold striped
Size: 2-2.5 inches
Characteristics: Social
Maintenance: Low
Habitat: 10+ gallon tank for a group of five
Compatible with: Just about anyone (no long-finned fish)
Diet: Omnivore
Life Expectancy: 2-5 years
Type: Egg-layer

Seasoned aquarium owners will often add zebra danios to their fish communities to promote good behavior among other species. Fish who do this are called dither fish and are known to encourage shy fish to play and aggressive fish to chill. Zebra fish are named for their stripes (and maybe because they frolic around like actual zebras to burn energy). They hail from India and adapt well to various conditions. While a 10-gallon tank is good for a small group of zebras, you’ll need something bigger if you want to add other varieties. Never get just one! They need to socialize—though they’ve been known to nip at longer fins.

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