Whenever there’s an exhibit or a home setup aquarium, freshwater (FW) stingrays are always the center of attraction, and I’m sure you’ll agree with at least one of these reasons. The main reason for their popularity may be how rare it is for the casual viewer to see one of them, as most of the fish ordinarily seen kept in aquariums are goldfish, arowana, or flowerhorns.

But to see what looks like a swimming UFO can bring about a big smile. Actually, fish keepers would have had more chances to see stingrays in the cooking pots of eateries, cooked in coconut milk, than seeing live ones in aquariums!Other reasons for its appeal is the knowledge that it has a dangerous, venomous tail; it’s something we Filipinos believe, from the folktales we’ve heard, to be used by mythical creatures called ‘aswang’.

Its unpredictable behavior, like its habit of hiding underneath the sand with just the eyes showing, or how groups of them tend to pile one on top of the other like pancakes, or swimming like a flying saucer, just hovering, staring at you. Lastly, there are the eye-catching patterns each species have. No wonder many Filipino hobbyists have succumbed to the allure of keeping FW stingrays, and they’re suddenly selling like hot pandesal everywhere.With websites and the surge in social media, it often only takes a click to acquire a pet these days. FW stingrays are among those that have become popular due to this, and hobbyists acquire them despite having little knowledge about how to keep them properly. It is our hope that this series of articles will help give all stingray hobbyists a better understanding of what this remarkable fish needs, where it started, how it reproduces…and even what to do in case you get stung!

Evolution of South American Freshwater Stingrays

There are two theories about freshwater stingray evolution: 1) these are marine rays from the Pacific Ocean that were trapped when the Andes mountains shifted; or 2) they are incursions of marine rays from the Caribbean area into rivers draining into the Atlantic ocean and are more closely related to marine rays of the genus himantura.Although it hasn’t been determined which of the two theories is correct, one thing is most likely: that it has evolved from marine rays that gradually adapted to brackish water and finally, to fresh water.

Stingray Classification Guide

FW stingray classification is very challenging; one reason for this is that there are a lot of variants, different morphs, the captive bred and those caught wild. The most critical thing to determine is whether it is a pure breed or a hybrid.Some favor the ‘pure’ ones because it’s the way the fish should look, especially those caught in the wild, while others prefer hybrids because of their unique appearance, especially if the outcome is superb. At the end of the day, it all boils down to one thing: what the hobbyist prefers.To give you an overview, we stumbled upon a P# index of stingrays on the Internet. You’ll notice that there are repetitions of species with different P# series. I’ve tried to ask about how this came about on international forums, but I was amused to discover that everyone seems to have the same question! The only sensible answer that I got was from Nick Symes: “…rays will vary in different parts of the river patterns in sp can change like every ray not the same but same name…” Basically, what he means is that those same species with different P# series were taken from different collection points. Now it’s up to you guys to decide.

Stingray Species Groups

Stingrays can generally be divided into two groups based on eye size: the “small-eyed” and the “large-eyed” rays.The small-eyed rays include the ceja and manzana rays, the coly and china rays, and the antenna rays. Small-eyed rays are more delicate: they cannot tolerate nitrate levels over about 200mg/l. They prefer soft water, so they are not that popular in the pet trade.Large-eyed stingrays—the group which includes the majority of rays imported in the pet trade—are more vigorous and hardy than the small-eyed rays. But take note: each species of large-eyed rays also have their own tolerance levels for different water parameters and environments.

This appeared as “50 Shades of Ray” in Animal Scene’s August 2015 issue.