Fish That Start With S – Discover 9 Unique Aquatic Species

Step right up and learn about fish that start with “S!”

Along this alphabet fish journey, we’ve discovered lots of great fish species that start with different letters. Now, we’re onto the letter “S.”

Did you know that over 80 fish species in the world start with “S?” (*)

In this article, we’ll share just a few of our favorite underwater friends starting with the letter “S” that you can add to your own home aquarium.

Overview of Fish Starting with “S”

Fish Name	Habitat	Average Size	Diet	Special Care Notes
Swordtail	Freshwater	Up to 5.5 inches	Omnivore	Prefers a mix of open space and plants.
Siamese Fighting Fish	Freshwater	2.5 to 3 inches	Carnivore	Needs a minimum of a 2.5-gallon tank; avoid strong currents.
Silver Dollar	Freshwater	Up to 6 inches	Herbivore	Requires a large tank; known to chew on plants.
Sailfin Molly	Freshwater to Brackish	Up to 4 inches	Omnivore	Thrives in slightly brackish water; males have a large dorsal fin.
Synodontis Catfish	Freshwater	4 to 12 inches	Omnivore	Some species swim upside-down; nocturnal.
Stingray (Freshwater)	Freshwater	Varies, some over 15 inches in diameter	Carnivore	Needs a large, sandy-bottomed tank; can deliver a sting.
Squirrelfish	Saltwater	5 to 12 inches	Carnivore	Prefers low lighting; nocturnal.
Strawberry Peacock Cichlid	Freshwater	Up to 5 inches	Omnivore	Known for striking red color; can be territorial.
Scarlet Badis	Freshwater	Around 1 inch	Carnivore	Suitable for nano tanks; prefers live foods.

Don’t Get Stabbed by The Swordtail (Xiphophorus hellerii)

• Size: Up to 5.5 inches
• Care: Medium to large tank, with a mix of open space and plants. These fish are tolerant to several water conditions.
• Fun Fact: Female swordtails don’t always need a male to reproduce – they can store sperm and have multiple batches of fry over time!

Swordtails are a captivating sight in freshwater aquariums with their elongated, sword-like tails. Originating from North and Central America, they add a delightful dash of color to tanks with their vibrant colors.

One of the most interesting things about Swordtails is their adaptability. This fish is happy in a range of water conditions, making it perfect for both beginners and seasoned aquarists. 

When setting up their living space, aim for a medium to large tank with ample swimming room. 

Remember, they’re active swimmers! 

A balance of plant life and open space is ideal. Friendly by nature, swordtails get along with most tank mates, but having multiple males might lead to territorial disputes.

The Betta’s Fancier Name: Siamese Fighting Fish (Betta splendens)

• Size: Around 2.5 to 3 inches
• Care: Have a minimum of a 2.5-gallon tank, and avoid strong currents. They also prefer slightly warm water.
• Fun Fact: Betta fish can breathe air thanks to a special organ called the labyrinth.

The betta, or Siamese fighting fish, is a standout among aquarium fish. With its flowing fins and an array of brilliant colors, it’s easily recognizable to many. 

Bettas are originally from the shallow rice paddies of Thailand and Cambodia, and they’re actually a labyrinth fish. This means they can breathe the air directly with a special organ!

Because of this, they’re able to thrive in low-oxygen environments unlike other fish. 

Though they’re often presented as an easy fish to raise by pet stores, bettas actually have very specific care rqureimetns to live happily. Small bowls aren’t good for them, and they need stable water conditions to thrive.

If you plan to get a male, they should be housed individually as they can get aggressive. However, multiple females can be put in a tank together, sometimes called a “sorority.”

Regular water changes, a balanced diet, and some hideouts will ensure your Betta lives a vibrant, happy life.

You’ll Always Be Rich With the Silver Dollar (Metynnis argenteus)

• Size: Up to 6 inches
• Care: Large tank with several hiding places. They’re plant munchers, so choose sturdy plants or offer vegetable-based foods.
• Fun Fact: They’re closely related to piranhas, but are peaceful by nature.

Silver dollars are peaceful schooling fish that look just like a silver dollar coin, hence the name. These unique fish are incredibly social and are at their happiest when kept in groups, so plan to get several!

However, you should keep in mind their potential size. Many of these fish reach upwards of 6 inches in length, so you’ll need a big tank to give them enough space. 

Because they love to chew on plants, you should get some hardy plants that can withstand gentle nibbles. You should also give them plenty of veggies to eat to deter them from wanting to eat the scenery. 

The Livebearing Sailfin Molly (Poecilia latipinna)

• Size: Up to 4 inches
• Care: These fish are suitable for both freshwater and brackish tanks. They also love plants and open swimming spaces.
• Fun Fact: Males have a large dorsal fin, which they flare out to impress females.

If you want an impressive addition to your tank, consider the sailfin molly. The males of this species have a massive dorsal fin that they flare out to find a mate – a beautiful sight to behold!

This graceful fish does well in both freshwater and brackish aquariums, as they tend to be pretty hardy. However, they do tend to do their best in at least slightly brackish water.

Sailfin mollies love plants, so you should plan to get lots of aquarium plants for their tank. They’re also livebearers, so you may be able to see them give live birth to their fries. 

As long as you have enough hiding spaces to let them feel safe (and both males and females, of course) you should see some little fries swimming around in no time. 

The Upside-Down Swimming Synodontis Catfish (Synodontis sp.)

• Size: 4 to 12 inches, depending on species
• Care: Just like other catfish, these are bottom dwellers. Provide them with caves and hideouts.
• Fun Fact: Some Synodontis species swim upside-down to scavenge food from under rocks and logs.

Originating from Africa, the Synodontis Catfish is a diverse group with species ranging from the spotted to the upside-down swimming varieties. 

Yes, you read that right. Some of these fish love to swim upside-down to nibble on food underneath rocks and logs!

Synodontis catfish are bottom-dwellers and are quite active during the night. Given their nocturnal nature, having caves or shaded spots in the tank will make them feel right at home. 

Their diet mainly consists of invertebrates, but they’re not very picky eaters and will happily munch on flakes and pellets. Just make sure they get enough to eat, especially if housed with more boisterous fish.

The Fierce Yet Beautiful Stingray (Freshwater) (Potamotrygonidae sp.)

• Size: Varies greatly, but some can be over 15 inches in diameter
• Care: Freshwater stingrays need large, sandy-bottomed tanks and meaty foods.
• Fun Fact: Stingrays have electroreceptors, allowing them to detect the electrical charges of hidden prey.

Yes, stingrays are considered fish! If you’ve ever seen a stingray in person, you know just how easily they can hypnotize you with their smooth movements.

Originally from South America, freshwater stingrays glide along the bottom of their home, grazing the sand and sometimes burying themselves in it. 

Because of their size and special needs, these fish are only recommended for experienced hobbyists. If that sounds like you, though, be sure to provide them a large tank with soft sand along the bottom. 

As carnivores, you should feed your stingray meaty foods to keep them happy and healthy.

Oh, and be careful when it comes to their barbed tail! If surprised or threatened, they can give a nasty sting. 

The Bug-Eyed Squirrelfish (Holocentrus adscensionis)

• Size: 5 to 12 inches based on species
• Care: Squirrelf fish need a saltwater tank with many hiding spots. They’re also nocturnal, so low lighting is best.
• Fun Fact: Their large eyes allow them to see better in the dim light of their nighttime environment.

Squirrelfish really just look like big-eyed goldfish, but they’re really much cooler than that. These fish are originally from the Indo-Pacific and Atlantic reefs, and their big eyes help them see better in the dark for hunting purposes. 

Because they’re used to low lighting, you should replicate this in their tank. They also love to explore caves and rocks throughout the day. 

Though peaceful, this species can be a bit shy (or should we say, squirrely?), so make sure you do everything you can to help them feel safe. Hiding spots and a varied diet are part, but you should also be careful with who you allow to be tankmates with your squirrelfish!

The Striking Strawberry Peacock Cichlid (Aulonocara sp.)

• Size: Up to 5 inches
• Care: These cichlids need a freshwater tank with many hiding spots due to their territorial nature.
• Fun Fact: Their bright colors aren’t just for show – males use them to attract females.

You didn’t think we’d leave this list without at least one cichlid, did you?

The strawberry peacock cichlid is known for its striking red color and is a favorite among freshwater aquarists. They can be territorial, though, so be sure to give them a large enough tank to have their own space.

You should feed your strawberry peacock cichlid a combined diet of pellets, flakes, and live foods to keep them healthy. 

The Tiny, Meat-Loving Scarlet Badis (Dario dario)

• Size: Around 1 inch
• Care: Small tank with plenty of hiding places. They also enjoy live foods.
• Fun Fact: Despite their small size, male Scarlet Badis can be quite territorial, especially during breeding times.

If you want to keep a small tank, the scarlet badis is perfect for you. This tiny, vibrant fish is incredibly peaceful, but is also known for its shy personality.

Because of this, you should be wary of putting them with extremely active fish. If you do, be sure to give them ample hiding spots to help them feel more secure. 

Though small, this species is carnivorous, so you’ll want to give it a diet rich in micro-live foods or high-quality prepared meaty foods. 

Swimming On

As you can clearly see, there are lots of great fish species out there starting with “S.” Hopefully, this list gave you some ideas of new fish to try out in your home fish tank. 

If you’ve ever raised any of these “S” fish before, be sure to tell us about your experience in the comments below. We would love to hear about it!

And before you go, be sure to check out some of our other fish by the letter articles, like Fish That Start With A, or Fish That Start With T.