Freshwater Stingrays are a diverse group of fish that are increasingly common in today’s specialty pet stores.
They are personable carnivores with an impressive appetite and many quirks that make keeping them a challenge.
That’s why I’ll be breaking down the types of Freshwater Stingrays and their care needs below!
What are Freshwater Stingrays?
Freshwater Stingrays are some of the most unique aquarium fish you could ever own.
As members of the superorder Batoidea, they are true rays just like their marine cousins. This also makes them close relatives of sharks and sawfish.
Sharks, stingrays, and sawfish have several features in common, including a flexible skeleton made of cartilage rather than bone.
They also have thousands of Ampullae of Lorenzini, electrosensitive pores that help them detect the electric fields all animals give off. This allows them to sense buried prey and hunt in total darkness.
Freshwater Stingray are found in tropical regions around the world and come in a variety of sizes and patterns.
No Freshwater Stingray species is truly small; even the Atlantic Stingray reaches a respectable foot in diameter. All require large aquariums with ample filtration, prefer fine sand substrates, and heavy feedings of protein rich food.
They are also personable fish that respond to hand feeding and even enjoy being touched. However their venomous stingers are a real issue and should never be ignored.
I specifically discuss handling Freshwater Stingrays and their venomous barbs below.
Common Types of Freshwater Stingray Species
There are dozens of Freshwater Stingray species available in the pet trade but only a few are commonly seen in specialty aquarium stores:
Tiger River Stingray
While moderately popular in the aquarium trade, the Tiger River Stingray is relatively unknown to science.
Closely related to Potamotrygon schroederi and other Amazonian species, it’s one of the larger Amazonian Freshwater Stingrays as well as one of the most sensitive to water quality.
The majority are wild caught and exported under crowded, stressful conditions so rehabilitating Tiger River Stingrays is always a chancey prospect.
However once healthy and eating properly they are a striking species, with a marbled golden brown and black color that helps then blend into the dappled shade of forest cover.
- Scientific Name: Potamotrygon tigrina
- Disk Diameter: Up to 28″
- Home Region: Peruvian Upper Amazon
- Price: $750-$1000
Ocelate Stingrays are one of the most widespread Freshwater Stingrays, found across the Amazon, Orinoco, Río de la Plata, and Mearim River basins, covering most of South America. When rivers flood they often end up in artificial ponds and canals.
As widespread as they are, Ocellate Stingrays are also one of the more popular rays in the aquarium trade.
While all Freshwater Stingrays are sensitive the Ocellate Stingray is easier than most species to care for.
- Scientific Name: Potamotrygon motoro
- Disk Diameter: Up to 24″
- Home Region: Across South America
- Price: $150-$300
Giant Freshwater Whipray
Also known simply as the Giant Stingray, the Freshwater Whipray is a massive, almost legendary animal when full grown.
As one of the largest freshwater fish on the planet, Freshwater Whiprays grow to nearly 12 feet long and over 7 feet in diameter. They will outgrow any normal aquarium well before then.
Determined aquarists should look at a pond or custom build aquarium to house one of these impressive fish.
Obtaining one is also a challenge as they are an endangered species. However, the occasional captive bred or smuggled Freshwater Whipray finds its way into the trade.
Giant Freshwater Whiprays have the longest barb of any Stingray species. At over 15 inches, a single unlucky venomous thrust could easily be lethal due to massive blood loss.
Like other Freshwater Stingrays, babies are born live, though already a massive 12 inches across.
- Scientific Name: Urogymnus polylepis
- Disk Diameter: Up to 7 feet and 1300 lbs
- Home Region: Southeast Asia and Indonesia
- Price: $300 when young
While they can survive in freshwater indefinitely, Atlantic Stingrays are truly euryhaline fish. They migrate constantly between freshwater, brackish, and ocean environments to find food, mates, and warm water.
They are inexpensive, native to the US, and one of the smaller Stingray species.
A true freshwater population exists in the St. John’s River in Florida. However the majority move in and out of freshwater from Mexico as far north as the Chesapeake Bay.
The long pointed snout and patternless brown color of the Atlantic Stingray makes them easy to tell apart from their true freshwater cousins.
- Scientific Name: Hypanus sabinus
- Disk Diameter: 10-12″
- Home Region: Atlantic Coast, North America
- Price: $100
Xingu River Stingray
Also known as the Black Devil Stingray, Potamotrygon leopoldi is striking, with a midnight black and creamy white spotted pattern.
Their bold color, sensitivity to water conditions, and rarity in nature make them some of the most expensive fish in the aquarium hobby. The Xingu River is a tributary of the Amazon and the only place Potamotrygon leopoldi exists in nature.
Currently export is banned, making captive bred the only (legal) option for Xingu River Stingrays. Fortunately, they are prolific compared to their relatives and can have 6 to 8 pups compared to other species that usually have 2 to 4.
- Scientific Name: Potamotrygon leopoldi
- Disk Diameter: Up to 18″
- Home Region: Xingu River, Brazil
- Price: $750-$1500
Porcupine River Stingray
Porcupine River Stingrays are popular with first time Freshwater Stingray keepers because they are an inexpensive and less sensitive species. Like many species, their name describes their home region.
As a smaller species, Porcupine River Stingrays do well in moderately sized aquariums as small as 125 gallons.
Despite their hardiness, proper attention to water quality is still mandatory as all Freshwater Stingrays are highly sensitive compared to other fish.
- Scientific Name: Potamotrygon hystrix
- Disk Diameter: Up to 16″
- Home Region: Upper Reaches of Rio de la Plata
- Price: $150-250
Many Freshwater Stingrays are captive bred as exportation becomes increasingly illegal and habitat loss causes their numbers to drop in the wild.
Identifying Freshwater Stingrays can be a challenge because they vary in pattern significantly even within a species. Many of the Potamotrygon are also closely related and will even hybridize.
Unscrupulous Asian fish breeders will often sell hybrids as unique species or color morphs so be on your guard when shopping for Freshwater Stingrays.
Potamotrygon Freshwater Stingrays are illegal to import, transport, or possess in several US States: Arizona. California, Florida, Georgia, Hawaii, Mississippi, Nevada, Oklahoma, Texas, and Utah. They are capable of naturalizing in the warmer states and are considered public health hazards in others.
Freshwater Stingray Care
Freshwater Stingrays are striking, intelligent, and rewarding to keep! However, as large, expensive aquarium fish, Freshwater Stingrays also offer several challenges that need to be carefully considered:
Selecting a Freshwater Stingray
Freshwater Stingrays are sensitive compared to other aquarium fish. Choosing a healthy specimen will make your life a lot easier.
Avoid Stingrays with open sores or wounds as they will heal poorly if the Stingray is stressed or water quality is even a little off.
Ask to observe the Stingray during feeding. Healthy Freshwater Stingrays are ravenous and should show a good response to meaty prey items.
A lack of appetite is a terrible sign unless the Stingray has only just arrived.
Freshwater Stingray “Death Curl” is something to be avoided at all costs. The outer edges of a Stingray will constantly curl upward rather than lying flat against the substrate.
While the causes aren’t known for certain, nervous system injuries caused in transit are a possibility, as is Death Curl being a general reaction to severe stress.
Never buy a Curling Freshwater Stingray. Note that the disk does naturally ripple as the Stingray swims; Death Curl is a visible, semi-permanent warping of the disk upward.
Lastly, you’ll want to inspect its poop! Freshwater Stingrays are invertebrate predators and often wild caught which means they can carry loads of internal parasites.
During transport, these parasites gnaw away at their resilience and can cause immense stress. Stringy or pale feces are a sign of a heavy internal parasite load that will need treatment.
Robust, dark, curly feces are indicators of good health and a hearty appetite!
Tank size is a bit of an issue with Freshwater Stingrays due to their unusual habits. They are wide fish that are extremely active but frequent the bottom levels of the aquarium. Therefore, height is far less important than floor area.
Custom aquariums and pools that are especially wide make the best enclosures. 125 gallon tanks (dimensions 72½ x 18½ x 23⅜ ) are the bare minimum for young Potamotrygon species as well as smaller species like Atlantic Stingrays.
For adult Potamotrygon Freshwater Stingrays 200 gallons is the bare minimum with larger always being better.
High aquarium volume is also important due to the copious amounts of ammonia and feces Freshwater Stingrays generate as well as their sensitivity to water conditions.
Substrate and Other Freshwater Stingrays Concerns
The two most popular options are offering silica-free fine sand substrates and bare bottom aquaria.
Sand aquariums are not only more aesthetically pleasing but allow the Freshwater Stingray chances to exercise their natural instincts to bury, dig, and hunt for food.
Often they will cover themselves in sand until only their eyes are exposed. Even when buried they continue to breathe normally thanks to the spiracles behind their eyes.
Bare bottom aquariums are easier to clean and make finding food easier for the Stingray. However, they offer little in the way of stimulus.
Freshwater Stingrays can’t grip glass the way they do sand and are constantly exposed whether they wish to be or not. And in my personal opinion the aquariums aren’t nearly as aesthetically pleasing!
Other decorations like plants, rocks, and driftwood should be chosen with care. Sharp rocks and driftwood can injure their disks and should be avoided. These decorations also take valuable bottom real estate from your Freshwater Stingray.
Plants will certainly be uprooted as they dig and root around constantly. However, plants that can attach to driftwood and rock like Java Ferns and Anubias are great choices for your Stingray tank.
Any aquarium heater in a Freshwater Stingray tank should be covered by a Heater Guard.
With their large body surface area and wandering tendencies, Freshwater Stingrays can be easily burned brushing up against an aquarium heater. Any heater large enough for a Stingray tank will be especially hot to the touch.
Water quality is the main reason keeping Freshwater Stingrays is a challenge. They are not only large carnivores, which means they create loads of protein-rich waste, but they have an unusual biology. They retain the biochemistry of saltwater fish, adapted to a freshwater environment.
In order to balance their internal chemistry, they create copious amounts of urine, including ammonia.
Their feces are also loose and when disturbed, fall apart and drift straight into the water column.
To top it all off, Freshwater Stingrays are also highly sensitive to ammonia, nitrites, and nitrates. The first two should be at 0ppm and nitrates at an upper limit of 10ppm.
Weekly partial water changes are essential as are heavy duty canister filters to keep your nitrogen cycle in check.
While the amount depends on the size of both your stingray and your aquarium, 50% weekly changes are not unusual.
- Temperature: 75-82F
- pH: 6.0-7.0
- Salinity: varies between species; from 0% to tolerating brackish conditions. Some species benefit from salt while others can’t tolerate it.
- Ammonia/Nitrite/Nitrate: 0ppm
Freshwater Stingray Tank Mates
Stingrays are opportunists and will take small fish at night when they are sleeping.
While carnivorous, Freshwater Stingrays are peaceful and easily bullied by large Cichlids, many predatory Catfish, and other boisterous tank mates.
Plecostomus should be avoided; they sometimes will latch onto the Stingrays from above and rasp mucus from their bodies, which is both stressful and infection-inducing.
Ideal companions are fish that will ignore the Stingray but can’t be eaten, including:
- Silver Dollars
- Community Cichlids like Angelfish and Severums
- Large Gourami
- Tinfoil Barbs
Feeding Your Freshwater Stingrays
Several daily offerings of meaty items, both live and dead, will be gleefully accepted.
Slices of white fish like tilapia, catfish, and carp are inexpensive and easily obtained fresh or thawed. Raw shrimp, scallops, mussels, black worms, and thawed cubes of smaller prey like tubifex and blood worms are better in the long run as Freshwater Stingrays prefer consuming invertebrates! Even terrestrial invertebrates like the occasional mealworm, cricket, or beetle will be happily eaten.
Leave the heads, scales, and shells intact on shrimp, small crayfish, insects, and small fish as well. Stingrays are one of the few vertebrates besides mammals that can effectively chew their food.
While they chew messily they obtain even more nutrition from consuming the entire organism – shells, organs, and all!
While all will accept a wide variety of carnivorous offerings, look into the particulars of your individual Freshwater Stingrays.
Some, such as the Xingu River Stingray, normally consume hard shelled mollusks and crustaceans, and appreciate crunchy fare on occasion.
While opportunistic, Freshwater Stingrays don’t consume fish often in nature.
Many aquarists hand feed their rays or use feeding tongs if the Stingrays struggle to get their fair share in a community tank.
Dealing with Freshwater Stingray Barbs
As you’re no doubt well aware, Freshwater Stingrays get their name from the venomous barb that runs along the tail.
Freshwater Stingray venom is severely painful and more potent than their marine cousins thanks to having more venom secreting cells along the length of the barb that create toxic mucus.
Young Freshwater Stingrays have a peptide cocktail of pain causing agents while adult Stingrays use proteins that cause inflammation and tissue death.
Species, diet, and water chemistry can also affect the quality of Stingray venom in unpredictable ways.
Although the venom is cardiotoxic, most injuries occur along extremities are are thus not as life threatening.
If stung, victims should immerse the affected area in water as hot as they can stand as heat denatures Freshwater Stingray venom. You should seek emergency help; while antivenom is unlikely and the wound itself is rarely serious, necrosis is a possible and very dangerous side effect of being stung.
If the barb breaks off in your flesh, you should definitely see a doctor.
As you may know, former legend Steve Irwin died after having a Stingray barb removed in the field. While you probably won’t be stung in the heart, Stingray barbs are serrated in such a way that they tear flesh when carelessly removed.
They are also sharp enough to lodge into bone if driven with enough force.
Clipping a Freshwater Stingray’s barb is a contentious topic among Stingray keepers.
On the one hand, Stingrays only use their barb defensively and only up close. Generally, you need to grab or otherwise provoke a Stingray into lashing out with its tail.
They don’t go on the offensive like a fencer and are intelligent animals that recognize their handlers.
Freshwater Stingray barbs also grow back within a few months if cut (or lost in the flesh of a predator). So trimming can be an unnecessarily stressful procedure that ultimately isn’t permanent.
On the other hand, being stung can be a serious affair.
Aquariums with Stingray petting exhibits clip their rays with no serious side effects for the safety of all guests. If you allow others to feed and interact with your Freshwater Stingrays it’s a good idea to keep them clipped.
As a modified scale, Stingray barbs also carry no nerves or blood vessels, so trimming causes no pain to the animal.
Breeding Freshwater Stingrays
Freshwater Stingray breeding is fascinating because these fish really are like few else on the planet. Their biology is strange; in some respects they are much like mammals and in others ways utterly alien.
Sexing Freshwater Stingrays
For starters, sexing Freshwater Stingrays (as well as all sharks and rays) is easy to do.
Male Freshwater Stingrays have twin specialized anal fins called claspers that are used to internally fertilize females much the same way that mammals do.
Male Stingrays have identical coloring but are usually smaller than females of the same age.
Female Freshwater Stingrays are larger and don’t have claspers.
They have thicker skin to fend off the biting habits of interested partners as well as twin oviducts that expand into uteruses when impregnated.
Again like mammals, Freshwater Stingrays are viviparous; they give birth to live, free swimming young rather than laying eggs.
While within the mother, baby Stingrays are nourished by a uterine fluid called histotrophe that is essentially milk for their young!
Conditioning Your Freshwater Stingrays
Time, space, and ample food is all that’s really required.
Freshwater Stingray breeding is not terribly difficult; the main hurdles are space, the time involved to reach sexual maturity, and the expense of each adult.
As I’ve said earlier, Freshwater Stingrays have fast metabolisms and prodigious appetites. Pregnant females need even more food and will even re-absorb developing young if food levels drop off.
Stingray pregnancies last roughly 3 months so you need to keep feeding constantly and of course, keeping a careful eye on water quality.
Specifics on breeding are hard to obtain due to the space requirements, relative rarity, and differences between species.
As a general rule, Freshwater Stingrays reach sexual maturity around 18 months to 2 years of age.
Sexually mature males have claspers that appear thicker; this is independent of body size. Hormonal triggers from nearby females often causes males to “ripen” when introduced to their tank.
Abundant and frequent water changes combined with constant food and sexually mature Stingrays signal that it’s time to reproduce.
Once they begin, female Freshwater Stingrays can raise and produce young almost constantly. Within 10 days of birthing her pups a female may accept a male for a new pregnancy! First time breeders may only have 1 or 2 pups with numbers increasing over time.
Males will bite the edges of the disks of females to encourage them to accept.
Once ready the male will bite and hold on while maneuvering to impregnate one of her uteruses with a single clasper, belly to belly. Copulation lasts less than 30 seconds before he releases her.
It can be hard to determine whether the female is pregnant. Observing the males is one way; they will mostly stop harassing her as they can detect through hormonal triggers that she’s no longer available.
Her appetite will also drastically increase, though Freshwater Stingrays are always ravenous.
As the young develop they will eventually swell her rear body and may even show slight motion through her skin in the late stages.
Raising Young Freshwater Stingrays
Young Freshwater Stingrays are born after a 3 month term, usually late at night to extremely early in the morning to avoid being found by predators.
The female will swim mid-water and release the young into the world.
Baby Freshwater Stingrays should be moved to a separate, spacious aquarium or pond for maturation as fully grown adults may consume them.
Each young Freshwater Stingray will be around 4 inches across and has a yolk sack that gives them 3 to 4 days of nutrition.
Live and fresh foods should be immediately offered, however. Live ghost shrimp, black worms, and small earthworms will be quickly consumed. You can eventually convert them over to thawed and fresh foods like pieces of shrimp and fish!
Young Freshwater Stingrays tend to show features from both parents.
If a dark male and pale female are bred together the young will be somewhere in between. This makes the hybrid Stingrays coming out of Asia especially attractive, with patterns of stripes and spots not seen in standard versions.