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A Fun and Fascinating Addition to our Aquatic Menagerie: Zoidberg the Teacup Stingray

Robert W. Bly, founder,

My teenage boys and I always look for unusual and interesting specimens in our local fish stores, and occasionally get so tempted that we buy and keep one. The latest addition to our aquatic menagerie is our new teacup stingray.

The teacup is a freshwater stingray on the small side. Our young specimen's main disk is about the size of your closed fist. A pointed tail extends a few inches out from the rear of the disk. The disk will grow to the size of a dinner plate and the tail will lengthen proportionally.

At the fish store, we were told that the sting is not poisonous, but that it can be painful. So you don't want to play around or do anything that would cause the ray to sting you in self defense.

We are keeping our teacup stingray in a 40-gallon tank. The fish store owner assured us he won't outgrow the 40 gallon tank, though elsewhere I've read that a 125-gallon tank is recommended.

You can use either gravel or sand as the substrate for your teacup stingray's tank. We chose sand because it gives a smoother, more natural surface for the stingray to travel over. Use a thin layer of sand, so that matter doesn't accumulate and rot in the substrate.

The teacup spends part of the time lying on the sand, and if startled, may partially cover itself with sand. Our teacup is pretty active, and likes to swim around the tank. They swim mainly close to the bottom, presumably looking for food.

The teacup stingray is an interesting-looking creature and fascinating to watch. Two small bulbous black eyes protrude from the front of the disk, next to which are two spiracles which resemble nostrils. Water is taken in through the spiracles and passes over the gills which extract oxygen.

Water is also taken in through gill slits on the bottom. The mouth, too, is on the bottom of the disk, and it's entertaining to watch the teacup feed.

Teacups prefer live food, and we feed ours live black worms. We buy black worms weekly at the fish store. They are kept in the refrigerator in a small plastic container, and inside are covered by clean de-chlorinated water which we just take from our tanks.

Since rays are bottom feeders, food must be placed on the sand, not dumped into the tank from the top. Use a plastic turkey baster or other long plastic tube with a bulb on one end and a narrow nozzle on the other to draw up water and worms from your container. Insert the baster into your tank so that the tip of the nozzle is just above the sand, and squeeze the worms out.

It takes a second for the teacup stingray to realize that live food is near. When he does, he lifts off like a flying saucer, skimming just above the sand surface until he comes to the wriggling mass of worms. Then he lowers his disk, completely covering the pile of worms.

The top of the disk expands and contracts repeatedly as the ray sucks the worms into his mouth. My younger son and I named him Zoidberg, because he eats like the Zoidberg character on Futurama. My older son prefers the name Garstin because it uses most of the letters in "stingray."

Choice of tank-mates is limited. Discus fish are compatible with stingrays and are beautiful but expensive. Angel fish and rainbows also get along with stingrays, look great in the tank, and cost a lot less. Do not add plecos to the tank. They suck a protective mucus coating off the disk, making the ray more susceptible to disease.

Our tank is sparsely decorated, mainly with two pieces of driftwood. We did not put a lot of decorations in the tank because we wanted to give the stingray a large area of clear and free sand on which to skim. They skim a lot, searching for food, and can draw buried worms or other food out from beneath the sand.

Teacups and other freshwater rays evolved from saltwater stingrays who wandered inland and got cut off from the ocean, and like their saltwater cousins, are fairly sensitive to chemical changes. Let the tank stand a few days before adding your teacup. We conditioned the water by adding an angel and a couple of rainbows first.

Have the water tested at the fish store to make sure the tank is ready for your ray. Make sure the store adds oxygen to the bag, and float the ray for 30 minutes so that the temperatures equalize; rays are sensitive to sudden fluctuations in temperature.

I am currently reading Freshwater Stingrays: a Complete Pet Owner's Manual by Richard Ross (Barron's, 1999) and find it both informative and useful.

Post script: after a couple of weeks with us, Zoidberg now recognizes that the plastic tube is his source of food. When I insert the tube with the tip on the sand, he immediately swims over to it and begins sucking the worms out!