Do you have a freshwater aquarium and want to keep something a bit special? Then let us show you some of the coolest freshwater aquarium fish available to the home aquarist.
In this article, we show you some of the most amazing freshwater fish that offer you something different to the usual Guppies ( Not that we don’t like Guppies).
Some of the fish in this Top 20 Amazing Freshwater Fish list will not be readily available in your local pet store or aquarium shop but they are suitable for home aquariums and can sometimes be ordered or tracked down with a little persistence.
We love simple community aquariums full of neons and guppies but sometimes you just want something a little different.
Here is our pick of the coolest freshwater aquarium fish-Top 20 amazing freshwater fish:
- Ornate Bichir (Polypterus ornatipinnis)
- Blue Diamond Discus (Symphysodon sp.)
- Frontosa Cichlid (Cyphotilapia frontosa)
- Dojo Loach (Misgurnus anguillicaudatus)
- GloFish®, Electric Green Barb (Puntius tetrazona)
- Silver Arowana (Osteoglossum bicirrhosum)
- Farlowella Catfish(Farlowella acus)
- Black Ghost Knifefish(Apteronotus albifrons)
- Fire Eel (Mastacembelus erthrotaenia)
- Reticulated Hillstream Loach (Sewellia lineolata)
- Tiger Oscar(Astronotus ocellatus)
- Boesemani Rainbow (Melanotaenia boesemani)
- Crocodile Fish(Luciocephalus pulcher)
- Royal Farlowella Catfish (Sturistoma sp.)
- Figure 8 Puffer (Tetraodon biocellatus)
- Archer Fish (Toxotes jaculatrix)
- Bumble Bee Goby (Brachygobius doriae)
- Elephant Nose (Gnathonemus petersili)
- African Butterflyfish(Pantodon buchholzi)
- Freshwater Pipefish (Doryichthys martensii)
Ornate Bichir ( Polypterus ornatipinnis)
Of all the species of Bichir, the Ornate (polypterus ornatipinnis) is undeniably the most handsome with its distinct beige and black marbled cylindrical body. This is not, however, what makes this fish, also known as the Dinosaur Bichir (clue), rank as one of the coolest freshwater fish!
This giant of the ‘upper jawed’ polypteridae, named for its upper jaw being generally longer than its lower jaw, has incredibly poor vision. To hunt the Ornate Bichir relies upon its excellent sense of smell and the cover of darkness. Waiting in its daytime refuge until prey swims by it then strikes taking invertebrates and small fish. Though fascinating to watch this again is not the Ornate Bichirs coolest characteristic.
What does make the Ornate Bichir a very, very cool fish is that it is the last surviving relative of a very ancient species with fossils discovered dating back to the Triassic period 200 million years ago! It is a true dinosaur of the water, hence one of its common names.
|Scientific Name||Polypterus ornatipinnis|
|Tank Size||150-180 Gallons|
|Water Conditions||Freshwater:77-83° F, KH 1-12, pH 6.5-7.5|
Blue Discus ( Symphysodon sp. )
The Blue Diamond Discus (symphysodon sp) is a challenging but highly rewarding fish to keep. It requires good mimicry of its natural environment within its aquarium and well-maintained water parameters. A minimum tank size of 50 gallons is also required.
What makes the Blue Diamond Discus so incredibly cool is its vibrant solid blue body teamed with its piercing red eyes. There is no doubting that the Blue Diamond Discus has to be one of the most attractive fish to house. Be warned, however, that health and overall mood of this beautiful fish can drastically affect its coloring.
On top of its striking good looks this fish has another cool quality; as an adult that has bred, it will produce a secretion through its skin. This secretion then feeds the Blue Diamond Discus young for the first four weeks of their lives! After this, the Discus parents will begin to leave and return to the young fry until they are self-sufficient.
|Scientific Name||Symphysodon sp.|
|Water Conditions||Freshwater: 79-86° F, KH 1-3, pH 6.1-7.5|
Frontosa Cichlid (Cyphotilapia frontosa)
The gorgeous regal beauty of the Frontosa Cichlid (cyphotilapia frontosa) is held in high regard with cichlid keepers and rightly so! They are big, bold, and a true aquarium centerpiece.
Growing up to a possible 14 inches there are actually, unbeknownst to many, several different types of Frontosa for you to choose from. The reason many don’t know this? Because they all look very similar and need a keen eye to differentiate between them. Typical easy to spot differences include the number of stripes on their bodies and the shades of blue on their fins!
Whilst the above may be an interesting fact about the Frontosa Cichlid, it is not what makes them cool! Their temperament is the amazing thing, and the way they switch from a gentle and tolerant community dweller to a defensive and fierce territory defender. Take it from me, someone who actually has one, nets will be mangled and fingers bitten if you mess with this guys space!
|Scientific Name||Cyphotilapia frontosa|
|Tank Size||60-80 Gallons Minimum|
|Color||Grey, tan and white|
Dojo Loach (Misgurnus anguillicaudatus)
The Dojo Loach (misgurnus anguillicaudatus) is not the most flamboyant of fish but it is strangely endearing with its facial bristles, slender eel-like body, and variety of colorations. It is not, however, what you can instantly see that makes this fish cool, but what you can’t!
Just below the eye, the Dojo Loach has sharp motile spines which are usually hidden within a pouch of skin. When removed from the water or stressed, however, the Dojo Loach erects them and they become visible. Since these spines are capable of breaking skin, this fish should be handled with care.
As if defensive spines were not enough the Dojo Loach also has another amazingly cool feature in that it can predict a storm! Known in Europe as the Weather Loach for this very reason it is believed these fish are sensitive to barometric pressure. When a storm is approaching, they become far more active, swimming frantically and jumping and splashing!
|Scientific Name||Misgurnus anguillicaudatus|
|Origin||Farm Bred, Singapore|
|Water Conditions||Freshwater: 50-82° F, KH 3-5, pH 6.5-8.0|
GloFish® 7 Species Available
It’s pretty obvious what makes the Electric Green Barb a worthy resident on this list of the 20 coolest freshwater aquarium fish but I’ll explain it anyway. It is the magnificent, vibrant and glow in the dark color that they display!
The original Glofish Ⓡ were genetically enhanced whilst still embryos putting a lot of people off keeping them. The Electronic Green Barb, however, is not dyed, it does not fade, and it is not genetically enhanced. Instead, they inherit their color from the parents who have been produced by using a fluorescent protein gene that is found in some marine organisms.
For the best achievable effect, Glofish Ⓡ Electric Green Barbs should be kept in a small school in a tank size of 30 gallons minimum by themselves. They can also be kept in a community tank with other peaceful fish where they will make a stunning central attraction.
|Scientific Name||Gymnocorymbus sp.|
|Water Conditions||Freshwater : 72-82° F, KH 4-8, pH 6.0-7.5|
Silver Arowana (Osteoglossum bicirrhosum)
It has to be said right from the start that the Silver Arowana (osteoglossum bicirrhosum) absolutely oozes cool appeal from every scale on its magnificent body. From its sheer size, 3 foot and over, to its shy but predatory behavior, this Jurassic monster of the water is cool, cool cool!
If pushed to pick THE coolest attribute of the Silver Arowana, it would have to be its outstanding hunting skills. In their natural habitat, they breach the surface of the water to snatch prey off low levels branches. They manage to make these mighty leaps by forming stunning anguine ‘S’ shapes with their bodies before springing up.
This must be amazing to see, which you can with care when feeding. Offering food on a stick or long tweezers above the water line will encourage your Silver Arowana to jump.
Take heed before running out to purchase one of these amazing fish, however, as they are not a species for the faint-hearted. Silver Arowana need humongous sized aquariums of 250 gallons or more and are best kept alone. They also have a voracious appetite and are not cheap to feed.
|Scientific Name||Osteoglossum bicirrhosum|
|Tank Size||240-260 Gallons|
|Water Conditions||Freshwater:75-82° F, KH 1-8, pH 6.0-7.0|
Farlowella Catfish(Farlowella acus)
Also known as the Twig Plec or Twigging Farlowella this armored catfish has over 25 known species that all look incredibly similar and for a very good reason. They are masters of resembling a simple twig and taking camouflage to a whole new level!
The majority of catfish are squat and bulky whilst the Farlowella is slim with an extended nose and trailing extensions on its tail. Team this with its brown coloring and darker brown lateral stripe and you have a fish that when amongst leafy and twiggy substrate is invisible.
Interestingly, not only does the Farlowella Catfish look like a twig but it also acts like one too! Generally, a slow swimmer that shuffles along using its mouth, this Catfish when attacked or disturbed in any way will more than likely drop like a falling twig to the bottom of its aquarium. Now tell me that’s not cool!
|Scientific Name||Farlowella acus|
|Water Conditions||Freshwater:73-79° F, KH 4-8, pH 6.5-7.0|
|Tank size||50 Gallons+|
Black Ghost Knifefish(Apteronotus albifrons)
There are a couple of reasons why the Black Ghost Knifefish (apteronotus albifrons) makes it onto our list of the top 20 coolest freshwater fish and they involve both looks and behavior.
Growing up to approximately 18 inches in length the Black Ghost Knifefish has to be one of the most stunning and yet underrated fish that you can keep in your aquarium. Jet black with small white markings on the head and tail, the Black Ghost Knifefish has a silhouette that resembles a knife blade. When it swims it does so by rippling itself from head to tail which moves the underside fin in a constant mesmerizing rhythm.
The second cool characteristic of the Black Ghost Knifefish is also related to their swimming and enables them to navigate and move around underwater objects in the dark whilst they are hunting their prey. What is this cool attribute? Well, it’s almost a superhero like in that the Black Ghost Knifefish is a weakly electrical fish that has an electromotor and electrosensory system. It picks up on electric fields through its skin and produces them through its tail. It is also thought that they use this cool adaptation to communicate.
|Scientific Name||Apteronotus albifrons|
|Water Conditions||Freshwater: 73-80° F, KH 0-10, pH 6.5-7.0|
|Tank Size||100 - 150 Gallons|
Fire Eel (Mastacembelus erthrotaenia)
The Fire Eel (mastacembelus erythrotaenia) is a member of the spiny eel family which are found In Africa and tropical Asia. They are not, however, true eels and are only named so because of their resemblance to one.
Requiring a tank of 77 gallons plus and with a predatory nature towards smaller fish, the Fire Eel is another of the aquarium hobbies monsters and a popular one. However, many keepers are surprised to find that this monster, rather than being nefarious is actually fairly timid!
Timid or not, the Fire Eels coolness comes from its eel-like features such as the long cylindrical body and pointed snout and also from its amazing colors that it has been named for. Down the sides of their dark brown bodies, they have bright orange/ red stripes that often consist of small lines and spots resembling flames. The tips of their anal, dorsal and pectoral fins have red flashes too.
|Scientific Name||Mastacembelus erthrotaenia|
|Water Conditions||Freshwater:75-82° F, KH 10-15, pH 6.8-7.2|
|Tank Size||120 Gallons|
Reticulated Hillstream Loach (Sewellia lineolata)
The small but perfectly formed Reticulated Hillstream Loach (sewellia lineolata) has a yellow to gold colored body with black markings all over except for its underbelly which is plain and greyish. It is identified from other similar species by the 3 to 5 black stripes that run laterally down the body.
Sadly the Reticulated Hillstream Loach is neither a well known or frequently kept species of fish which is a shame as not only does it have cool attributes but it is also an ideal community choice for those with smaller tanks wanting a bottom-dwelling species.
Specially developed by nature the fins of the Reticulated Hillstream Loach allow them to attach to flat areas and rocks in fast-moving streams which are their natural habitat. They need strong currents in the home aquarium to thrive, be happy and display their coolest behavior!
Where there is a strong current the Reticulated Hillstream Loach will not simply swim to their next resting place, they will glide! Launching themselves from the elevated rock they are on they will use the current to simply float before alighting and stopping on another hard surface.
|Scientific Name||Sewellia lineolata|
|Water Conditions||Freshwater:64-72° F, KH 10-15, pH 6.5-7.5
Tiger Oscar(Astronotus ocellatus)
Tiger Oscars are one of the most interesting fish available to the home aquarist. They are big and semi-aggressive fish and should only be housed with equally large fish.
Many people make the mistake of buying these fish when they are small and cute and costing very little but soon realize that they are monsters and outgrow most fish tanks.
Care wise, Oscars are a large fish and need an aquarium size to match their bulk, possibly up to 3.5lbs! They are, however, moderately hardy fish and in turn relatively easy to keep. This, alongside their beautiful coloring and markings, makes them an extremely attractive fish to keep.
Read our full review on the Tiger Oscar Fish here or read all about how big Tiger Oscar can grow to.
|Scientific Name||Astronotus ocellatus|
|Color||Black, Orange, Red|
|Origin||Amazon, South America|
Boesemani Rainbow (Melanotaenia boesemani)
The Boesemani Rainbow (melanotaenia boesemani) is an absolutely stunning fish that could not be ignored when it came to creating this list. They are full of vibrant color and swim with a joy and speed that cannot be matched.
As a juvenile, the Boesemani Rainbow does not display any of the color and vibrancy that it will develop as it ages, but don’t be put off by their young coloration. By the time your fish is 12 months old, it will have the trademark light blue from head to midbody and yellow darkening to bright orange to its tail.
To achieve the best visual effect and for their benefit as skittish fish, the Boesemani Rainbow is best kept in shoals of 6 to 8 specimens. It is not advisable to keep them with much smaller or slow-moving fish due to the Boesemani Rainbow swimming at the speed of light. Also, bear in mind that when not kept in an aquarium with stable and correct water parameters their coloring will dim.
|Scientific Name||Boesemani Rainbow (Melanotaenia boesemani)|
|Origin||Farm Raised - Thailand|
|Color||Blue, Orange and Albino|
Crocodile Fish(Luciocephalus pulcher)
Named for its camouflage markings and patient predatory behavior as an ambush hunter the Crocodile Fish (luciocephalus pulcher) has an elongated body with a dominant stripe from mouth to tail and irregular blotches all over. The head and mouth of this species is huge and accounts for up to a third of its entire size!
This mix of a large head and mouth combined with its predatory nature is what makes this fish rate on this list of top 20 coolest freshwater fish. Lying motionless the Crocodile Fish waits for small prey to swim by within striking distance before lunging forward and extending its mouth in a net-like fashion. Surrounding the entirety of its prey it then closes its mouth.
If your cool freshwater fish becomes ill or starts to show unusual behaviors then read our complete guide to diagnosing and treating many of the common diseases in our complete guide.
As a piscivore, the Crocodile Fish will snack on anything that it can fit in its large mouth so they should not be housed with other species that will fit. At an adult length of around 7 inches, at least 2 inches of this is the mouth so species under this length should not be considered as tank mates.
|Scientific Name||Luciocephalus pulcher|
|Origin||Far East, Farm Raised|
|Water Conditions||Freshwater:72-79° F, KH 0-10, pH 5.5-6.0|
|Tank size||30+ Gallons|
Royal Farlowella Catfish (Sturistoma sp.)
The Royal Farlowella (sturistoma sp) is a close relative of the Farlowella Catfish (Twic Plec) that featured earlier in this list. Unlike the very slender Twig Plec, however, it is a little more broad and outgoing.
Although it is a little more stocky than its relative the Twic Plec, the Royal Farlowella still has the same long narrow nose and long skinny whiptail. It differs in color though being green to yellow.
Behavior wise the Royal Farlowella is a little more flamboyant than the Twig Plec, if that can be said of a fish that is designed by nature to blend into its surroundings and not be noticed? Unlike the twig plec, however, the Royal Farlowella will be seen moving around and feeding throughout the day.
Care wise they are not difficult and only require an aquarium size of around 30 gallons. They are, however, not widely available and are frequently mislabelled in local fish stores. This is a common problem with all the Farlowella species so you will need to really know what you are looking for.
|Scientific Name||Sturistoma sp.|
|Tank Size||30+ Gallons|
Figure 8 Puffer (Tetraodon biocellatus)
The automatic assumption for the reason the Figure 8 Puffer (tetraodon biocellatus) makes it onto the list of the top 20 coolest freshwater fish will be that it is a species capable of puffing up. This is not, however, the case and whilst the puffing is an incredible sight it is not cool in the slightest and here’s why.
The Figure 8 Puffer knows instinctively how to puff from birth. They only perform this action, however, when they feel threatened or are scared. In these situations they unhinge their jaws, gulp in water, swallow it and their stomachs puff until they are roughly three times their original size.
Once they feel they are safe, they then expel the water in small amounts so as not to take in too much air. Taking too much air in when expelling the water can be fatal and this is why their puffing is not cool!
What is amazing about these fish and the main reason that you should keep them is that they are full of personality, entertaining and look so, well the only word for it, is cute? They have a short rounded body with a large head and protruding eyes. Coloration is a dark grey upper body with green to yellow patterning.
These patterns have a huge variation and can be lines, circles, dots, and stripes. The Figure 8 Puffer is a very striking fish.
|Scientific Name||Tetraodon biocellatus|
|Water Conditions||Freshwater:75-82° F, KH 8-15, pH 7.0-8.0
Archer Fish (Toxotes jaculatrix)
With their triangular shaped body, elongated black spots and primarily silver body the Archer Fish (toxotes jaculatrix) is striking and attractive without being overly showy. They do, however, make quite a sight when kept in a species only tank in a shoal of six plus and with the correct care.
Requiring a tank that is at least 125 gallons, with a length of around 5 feet, the Archer Fish fares best with a paludarium setup that has twigs and plants above. Team this setup with live food such as crickets and you will see the coolest natural behavior in the aquatic hobby.
Archer Fish are famous for their ability to shoot a jet of water at insects on branches and twigs causing them to fall into the water and become a meal. Believe it or not, these jets can reach a target over one meter away and may be aimed at their keeper in the home aquarium. Archer Fish are renowned to lack patience when it comes to waiting for food.
|Scientific Name||Toxotes jaculatrix|
|Tank Size||90 Gallons+|
Bumble Bee Goby (Brachygobius doriae)
The truth is that there is not one specific thing about the Bumble Bee Goby (brachygobius doriae) that makes it remarkable. Rather it has a series of characteristics that make it super cool.
The Bumble Bee Goby really is a bit of an oddball and a unique looking bottom dweller. It really does resemble a bumble bee with its black and yellow striping and short squat body. Unlike most bottom dwellers, however, it does not travel along the substrate, rather it swims quite actively both day and night.
Best kept in a species only tank in shoals of six plus the Bumble Bee Goby has the capacity to be a happy-go-lucky fish or a real grumpster. Which personality type you get really is hit and miss. They are, however, all territorial and will bicker amongst themselves by chasing and pestering one and another without actually inflicting any harm.
|Scientific Name||Brachygobius doriae|
|Water Conditions||Freshwater:72-84° F, KH 9-19, pH 8.0-8.2|
Elephant Nose (Gnathonemus petersili)
The Elephant Nose (gnathonemus petersii) is not a species of fish for everyone. They are timid and nocturnal and extremely sensitive to water conditions. In fact, they are so sensitive, not that we advocate this at all, that they have been used in countries to test water quality by government water departments.
Despite these things, the Elephant Nose is a fish that you absolutely will want to keep and this is because of their truly cool appearance. A thin species with an oblong shape, dark brown to grey coloration and white markings this fish also has a trunk like nose, hence the name. This trunk is not there just to enhance the Elephant Noses appearance, however, it also has a function.
Like the Black Ghost Knifefish, the Elephant Nose emits electrical impulses through its trunk-like nose. These electrical impulses help them guide their way through the darkness where they cannot see very well due to poor eyesight.
|Scientific Name||Gnathonemus petersili|
|Water Conditions||Freshwater:73-80° F, KH 0-10, pH 6.5-7.0|
|Tank Size||50 Gallons+|
African Butterflyfish(Pantodon buchholzi)
Dating back over 100 million years the African Butterfly Fish (pantodon buchholzi) has a silvery brown to green coloration with black markings and of course, as the name suggests, butterfly-shaped pectoral fins.
These fins, no doubt, make this fish incredibly attractive to view but being beautiful is not the purpose of them. They, in fact, serve the African Butterfly Fish in two respects.
When resting at the surface of the water the coloration and shape of the African Butterfly fish with its pectoral fins spread gives this fish the appearance of a leaf floating on the surface. This, in turn, protects them from predators for the majority of the time. When it doesn’t, however, the butterfly fins serve another purpose.
Along with the caudal fins they are used for this fish to make incredible jumps away from predators which can be several meters in length. These jumps are also made to catch prey in the form of insects.
|Scientific Name||Pantodon buchholzi|
|Water Conditions||Freshwater:75-86° F, KH 1-10, pH 6.9-7.1|
Freshwater Pipefish (Doryichthys martensii)
Reaching around 6 inches in length and requiring a 30-gallon aquarium for one the Freshwater Pipefish (doryichthys martensii) is a very much underrated and overlooked cool freshwater fish.
Black and silver in coloration with an eel-like appearance these fish are also commonly referred to as the Long Snouted Pipefish and Black Barred Pipefish. Long-snouted because they have a long snout and black barred for the stripes that run down the length of their long slender bodies. Interestingly they are related to the seahorse who share a similarly shaped snout and head.
Another oddball of the freshwater species the Freshwater Pipefish will constantly roam their aquarium in search of tidbits of food. They move rather sluggishly making them fun to watch. Personality wise they are shy but regal and do not make the best community tank mates. If possible, they should be kept in a species only aquarium.
|Scientific Name||Doryichthys martensii|
|Water Conditions||Freshwater:75-82° F, KH 5-19, pH 6.0-8.0|
Final Thoughts: Coolest FreshwaterAquarium fish
Freshwater fish have some of the most amazing and coolest fish available to fish keepers. Lots of people talk about saltwater fish being the best fish to keep but in our opinion, there are some cool freshwater fish that will give saltwater fish a run for their money.
If you love your saltwater fish you may be interested in our 13 COOL SALTWATER AQUARIUM FISH post which has some lovely fish, but they’re not for everyone.
Freshwater fish keepers are dedicated fishkeepers and they stick to what they love best FRESHWATER FISH.
With freshwater fish, there are hundreds of species to choose from and they come in all shapes and sizes from the tiny Neon Tetras to the massive Red Tail Catfish.
Freshwater fish are also in general, easier to keep than saltwater and less expensive. In recent years Aquascaping has become very popular, it’s like creating an underwater garden with amazing scenes. I have even seen them with underwater waterfalls made with sand. Nothing looks better than a beautifully scaped garden with a large shoal of Cardinal Tetras.
We hope you like our article and hope we have convinced you to go out shopping for some of the coolest freshwater fish in our post.
Good luck and happy fishkeeping Forever!
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