Home » Aquariums » Home Aquariums » Freshwater Stingray Guide for Aquarium Keepers and Researchers

Freshwater Stingray Guide for Aquarium Keepers and Researchers


Freshwater Stingray Guide for Aquarium Keepers and Researchers picture

Peter is using his 600 gallon custom built aquarium for the observation and research of freshwater stingrays. Peter has been observing and keeping Amazon fish species for many years and has taken a special interest in the freshwater rays. There is little reputable documentation on the keeping freshwater stingrays such as the details of ideal tank conditions, behavior patterns, and long term life-cycle statistics. Peter's research could give us new insights into the preferred habitats and behaviors of wild stingrays as well.

The stingrays are fed silver-sides, large shrimp, ghost shrimp, bloodworms, and night crawlers. Peter has started his project with one 5 inch potamotrygon leopoldi male and two 7 inch potamotrygon hystrix shown in the photos on this page and in the video below. The darkest one is leopoldi.

The tank uses an HMA three stage reverse osmosis filter that preserves desirable salts. Some additional enhancements include a 55 watt UV sterilizer, two 2400 GPH pumps, and a digital titanium heater. Peter's stingray aquarium features a continuous-drip closed system to control the constant flow of fresh water so it never needs water added manually.

Peter will collect data about the leopoldi and hystrix at intervals of their life and publish that data for biologists and other interested parties. Peter has started a fund-raising project to support the research & discovery of freshwater stingrays like the leopoldi at http://www.indiegogo.com/stingrays. His research proposal to the Florida Fish And Wildlife Conservation Comittee is shown below.


Peter's Accepted Research Proposal to the Florida Fish and Wildlife Conservation Commission:

Non-native Conditional Species Research Proposal

Potamotrygon Genus

From: Peter Larsson

Date: April 23rd 2012

Subject: Research proposal, Potamotrygon species, “Freshwater Stingray”

Proposed Research Topic

Behavioural and scientific study of the Potamotrygon genus to understand their adaptability to different water conditions and environments outside of their native habitat.

Being extremely sensitive to water conditions and said to only thrive in relatively soft, acidic water parameters with a constant temperature of ca 24-26.5 °C. Any fluctuation in their environment has been known to adversely affect their health and this study will determine whether or not the specie can adapt to different conditions other than what’s found in their native waters of the Amazon River basin.

Objective and Significance

Freshwater stingrays of the family Potamotrygonidae contain three genera Partrygon, Plesiotrygon, and Potamotrygon. These stingrays are endemic to limited South American waters including the Amazon where they are found in slow flowing, clean waters. Some species are restricted to a single basin or river system making them very rare and living in parameters not found in neighboring waters. In this study I will research and focus on a select few species of the Potamotrygon genus including but not limited to:

  • Potamotrygon hystrix (Porcupine river stingray)

  • Potamotrygon leopoldi (White-blotched river stingray)

  • Potamotrygon motoro (Ocellate river stingray)

  • Potamotrygon menchacai (Tiger river stingray)

  • Potamotrygon schroederi (Flower river stingray)

These species are found primarily in waters with a pH of 6.25-6.75, a hardness of 150-200 ppm and a constant temperature range of 24.0-26.5 °C, while salinity is minimal. Being very sensitive and unlike most fishes found in the Amazon, they require ammonia and nitrite (NO2) free waters with nitrates (NO3) being lower than 40ppm in order to thrive. Intolerant of changes in these parameters, I want to explore exactly how sensitive this genus is to fluctuations and when exposed to waters outside of their native habitat. Such a study will give insight on whether the Potamotrygon species can survive in local waters in Florida and other states year around.

Research Design


I will conduct my study in a controlled, sealed indoor environment with no outside facilities whatsoever. The amount of rays will not exceed 4-5 at any one point to ensure enough time and resources are spent conservatively and wisely per ray. Each ray will be acquired as pups or juveniles from a selected few importers and/or breeders to study and understand their growth patterns and overall behavior while being subjected to minute changes in their environment. Each ray will be monitored on a daily basis throughout their entire lifespan, which has also never been officially been documented but projected to be around 10-15 years.


A 244cm x 122cm x 76cm, 2270 liter (96”x48”x30”, 600 gallon) acrylic aquarium will be the rays main holding tank. The 32 square foot footprint which is more than adequate to hold up to 6 rays for life as they reach their full size which can be anywhere from 12-24” wingspan depending on the sex and specie. Separate holding tanks, aquariums and quarantine facilities of different sizes will be as follows:

  • 114 liter (30 gallon) aquarium

  • 38 liter (10 gallon) aquarium

  • 4 large plastic containers

  • Various feeder tanks

Each tank will have lids, including the separate holding tanks which will be in a separate room from the main housing unit where the majority of the studies will be performed and documented. There is absolutely no chance of escape and at no point will any ray ever be subjected to native environments outside of their housing facilities.

Prior and during a critical and/or disastrous situation, all fish will be housed in fully sealed containers and moved to the safest place in the facility. In the event of power outages, a generator will be on hand to provide electricity to the filtration.


Due to the extreme sensitive nature of these rare rays, an abundance of filtration is a must in order to keep them healthy. An incoming water line on a constant drip through an HMA (heavy metal axe) filter to remove all chlorine, chloramines, ammonia along with other harmful particles and substances while still keeping essential minerals will be in use at all times. This eliminates the need for common chemical tap water conditioners and is the closest thing to the natural water found in the Amazon.

A free standing wet/dry sump with bio balls for biological filtration along with a pre-filter pad and sponges for mechanical filtration will be in place for the main housing tank but as a separate unit. In the sump itself, there will be a water discharge through a closed drain system that terminates in a dry-bed wastewater in a fenced in area on private property. The constant flow of freshwater from the drip system is designed to keep nitrates below 40 ppm.

The separate holding tanks will have either canister or hang-on-back filters with no drip system or drain. Water changes will have to be performed manually on a weekly basis.


To mimic natural light found in the rays’ natural habitat, a top-of-the line LED energy efficient strip light that projects a 12K spectrum will be mounted on the housing facility. A lunar mode will also be installed to replicate earth’s natural 24 hour cycle.

A UV sterilizer which is essential to eliminate harmful free floating microorganisms such as bacteria, algae, and parasites is going to be used at all times to ensure the safety and health of each ray.


Potamotrygon rays eat primarily only live foods such as shrimp, fish, crayfish, worms and other small invertebrates. A refrigerator/freezer will be dedicated to house all of the necessary foods and also the deceased carcasses of every ray until disposed of according to Florida Fish and Wildlife Conservation Commission’s standards.


Rays typically do not react well and will succumb to many common tropical fish medications. Some that are safe will be on hand and include:

Bacterial and fungal infections: Jungle laboratories Binox, Nitrofurazone + Sodium Chloride

External parasites: Bayer Droncit, Praziquantel

Internal parasites: Thomas laboratories, Metronidazole


I will use my expertise of over 20 years of keeping tropical freshwater fish, mostly from the Amazon region to research and analyze Potamotrygons. I will engage in a lifetime study of every ray acquired and the process of subjecting the rays to different water chemistry such as; pH, temperatures, nitrates, hardness, tank mates and housing. This will be done at very limited intervals until I conclude how they handle the different parameters than what they are used to in the wild. Every step of the research will be documented and shared with other enthusiasts, scientists and the Florida Fish and Wildlife Conservation Commission if they wish.

I have no intention on breeding the rays and this research is mainly focused on the sensitivity of the Potamotrygon rays and whether they can handle different water parameters and if so, at what rate of change is appropriate for them to thrive and survive.

Theoretical Framework

Research regarding the freshwater stingrays, including the Potamotrygon species from the Amazon River, has very little to limited documented scientific research available. However, Dr. Richard Ross is the pioneer and expert on these fish and has two publications available which will guide me throughout my studies:

  • Freshwater Stingrays from South America (AQUALOG Special)

  • Freshwater Stingrays (Barron's Complete Pet Owner's Manuals)

I will also interact with other aquarists in other states and countries who keep and research Potamotrygon’s to share knowledge and advise each other on safe practices when handling the rays.


  1. Ensure filtration and housing has thoroughly gone through the nitrification process.

  2. Acquire rays as pups from authorized importer/exporter or breeders.

  3. Quarantine every ray to ensure health before introducing them to large housing rays

  4. Change water parameters on a weekly to monthly basis and document the results. Each parameter will initially be tested individually until all have concluded and then they will be tested simultaneously starting with two at a time. Once either species of the rays react adversely to the changes, they will be safely returned to their optimal environment to ensure their health is never jeopardized.

    1. Temperature will be adjusted via an 800w titanium thermometer with a digital controller at 1 degree Fahrenheit on a weekly basis to understand the minimum and maximum ranges. Minimum ranges will be tested during the winter season to avoid the use of chillers.

    2. pH will be gradually adjusted on a monthly basis from their preferred range of 6.25-6.75 to a minimum of 5.0 to a maximum of 8.5. This will be done by using buffers and test kits.

    3. Water hardness will be tested from their ideal range of 150-200 ppm to:

      1. very soft 0 to 70 ppm 0 to 4 GH (dH)
        soft 70 to 135 ppm   4 to 8 GH (dH)
        medium hard   135 to 200 ppm   8 to 12 GH(dH)
        hard 200 to 350 ppm 12 to 20 GH (dH)
        very hard  over 350 ppm       over 20 GH (dH)

    4. Nitrates (NO3) can be tested by simply adjusting the flow of the drip/drain system and will be done accordingly as the ideal ppm is heavily debated with researches.

    5. Ammonia and nitrites (NO2) will not be tested as it this will permanently injure and kill any and all Potamotrygon rays.

  1. Interview experts from different states and countries to get an understanding of their research while at the same time sharing my knowledge and experience.


Each ray will spend their lifetime at my facilities in order to learn their sensitiveness to and adaptability to different water chemistries at all stages of life.

Housing and Filtration set up May 7th

Acquiring Rays Upon permit approval

Each parameter change will be done in a minimum of 3-6 month intervals during the ray’s lifespan at different stages of life. The first parameter will be tested once the rays are fully acclimated and healthy, projected to be around Q3 of 2012.


This research will be privately financed and will not rely on grants or public funding of any sort. Most housing, filtration, lighting and supplies are already in place.


Being granted the non-native conditional specie permit hangs in the balance of my research. If granted, the limitations would be the ability to acquire these rays and to ensure they are healthy, strong and free from disease and parasites, and since most specimens are imported, it can be difficult to ensure they are free from such ordeals.


Ross, Richard. Freshwater Stingrays from South America (AQUALOG Special). Hollywood Import & Export Inc.; 1 edition. September 1999.

Ross, Richard. Freshwater Stingrays (Barron's Complete Pet Owner's Manuals. Hauppague: Barron's Educational Series. July 1, 1999.

Axelrod, Herbert. Dr. Axelrod’s Atlas of Freshwater Aquarium Fishes, Ninth Edition. Neptune City: T.F.H Publications. 1999.

Butler, Rhett. Water Chemistry. 1994-1995, http://fish.mongabay.com/chemistry.htm, (Visited April 20th 2012).

Freshwater Stingray Guide for Aquarium Keepers and Researchers photo


Fresh Content...

Best Largemouth Bass Fishing Beginners Guide picture Best Largemouth Bass Fishing Beginners Guide How to Catch Catfish picture How to Catch Catfish How to Catch Big Fish on Topwater Lures picture How to Catch Big Fish on Topwater Lures Beginner Fly Fishing for Bluegill picture Beginner Fly Fishing for Bluegill
Florida Predators Fun Facts picture Florida Predators Fun Facts Trout Fishing in the Blue Ridge Mountains picture Trout Fishing in the Blue Ridge Mountains Fishing Games and Simulations picture Fishing Games and Simulations Summer Sea Trout in Northeast Florida picture Summer Sea Trout in Northeast Florida
Welatka Fish Hatchery picture Welatka Fish Hatchery Pellicer Pond picture Pellicer Pond


Post your comment or review here...

Review or Comment:


Comments & Reviews

Recent Posts

Rating: 5/5
Title: Freshwater Stingray Guide
by: Jackson 2016-10-21

Nice information about Freshwater Stingray