Feeding Your Pet Stingray - The Essentials of Maintaining a
Varied Diet
Stingrays will eat a wide variety of foods. Maintaining a varied
diet is extremely important in captive animals, as monocultural
diets incur a risk of nutritional deficiencies. Stingrays are
very active, and should be fed at least once a day, preferably
twice or even three times daily. The daily diet can be varied in
order to create some environmental enrichment as well as
balanced nutrition for the rays.
First Foods
First foods for newly acquired rays should be blackworms or
tubifex worms. These foods seem to be the most readily accepted,
and are small enough to be inadvertently ingested either by
mouth or through the spiracle, thereby giving the ray an
opportunity to taste these possibly unfamiliar foods by chance.
Foods that have been used for very small specimens, such as the
teacup rays, are small insect larvae such as mosquito larvae,
small shrimp known as ghost shrimp or glass shrimp, live adult
brine shrimp, and blackworms. Chitinous foods such as shrimp
provide less nutritional value than do soft-bodied foods, and so
should not be used as sole food items.
The best way to be certain that your new stingray is feeding is
to watch the spiracles as the ray passes over food on the bottom
of the tank. If it is eating, you will see the spiracles opening
and closing rapidly, or fluttering, as the food is ingested and
water is passed from the mouth and out the spiracles. Once you
observe a newly acquired ray readily feeding on black-worms or
redworms introduce finely chopped night crawlers in small
quantities. Once stingrays recognize these as food, most will
readily eat them. Later, experiment with other types of food.
Types of Food
Live Foods
Feed live foods, including blackworms or tubifex worms, in
quantities adequate to allow a small amount to be left in the
tank so the rays can browse later. However, when cleaning the
substrate, note whether a significant amount of living worms is
present; blackworms and tubifex worms will colonize the
substrate if not eaten and add to the nitrogenous waste
production in the aquarium.
Nonlive, Nonaquatic Foods
Chopped earthworms, redworms, or night crawlers and any nonlive,
nonaquatic foods should be fed in smaller quantities to prevent
any overlooked food from decomposing in the tank. Keep in mind
that stingrays have relatively small mouths-a 10-inch (25-cm)
ray may have a mouth that is 1/2 to 3/4 inch (13 to 19 mm) wide,
so chopped food items must be small enough to be eaten easily.
If a ray ingests a piece of food and repeatedly spits it out and
ingests it again, this usually indicates that the particle is
too large. Some ray species, such as antenna rays, have
extremely small mouths relative to their size.
Once acclimated, rays often develop techniques for eating larger
pieces of food; for example, newly imported rays may have
difficulty consuming even small chopped pieces of night
crawlers. Eventually, however, they learn to eat an entire worm
by sucking it into their oral cavity without chewing. Newly
acquired rays also often ignore feeder goldfish but they quickly
learn to chase down and consume feeders, even learning where
they hide in the tank.
Commercially Prepared Foods
Stingrays may learn to eat other unfamiliar foods such as brine
shrimp, pellet foods, or other commercially prepared foods.
While there is probably no harm in offering these foods to rays,
it is best to use fresh, live, or frozen foods as the dietary
staple. Although stingrays often do not initially accept frozen
or other nonliving foods, they may soon learn to eat these foods
after they have been acclimated. A benefit of frozen foods is
that they are less likely than live foods to introduce diseases
or parasites.
Hand-feeding
Occasionally, a well-acclimated specimen will fail to gain
weight, even though you are offering enough food. Several things
may cause this problem; the most likely possibility is that it
is not competing efficiently for food against other fish in the
aquarium, or it may have a parasitic infestation. Stingrays
occasionally do not seem to learn where foods can be found
during feeding times, and are always in the wrong part of the
tank during those times. In these cases, it is helpful to
hand-feed such specimens. By this I do not mean feeding with
your hands. Although some aquarists do this with stingrays, I do
not recommend it because of the possibility of being
accidentally stung. Remember that stingrays are wild animals,
and no matter how accustomed your specimens become to your
presence, it is impossible to always accurately predict their
response to humans. Instead, you should always perform the
hand-feeding of specimens with long forceps or a similar
instrument. Stingrays generally avoid metal objects and appear
to be frightened by metal; however, because they can sense
metal, they will quickly learn that when there is a metal object
in the aquarium, food is being offered. In this way, you can
teach your stingray to feed directly from forceps, and
selectively feed it more food.
Simply hold a night crawler (or a piece of night crawler) in the
forceps, and hold the worm in the aquarium so that the ray can
touch it with its fin. It should eat the worm immediately. After
a few feedings in this manner, allow the forceps to touch the
ray while it is eating the worm. It will quickly learn to
associate the forceps with feeding and soon you will find that
the ray will pounce on the forceps as soon as it touches it,
eagerly looking for a treat!
How Much and How Often
The key to having well-fed stingrays in your aquarium is
providing plenty of food. Unlike most fish that swim quietly
between feedings, stingrays search constantly for food, looking
under and around tank ornaments, moving driftwood, rocks,
filters, and even other fish! This high activity level
translates to a high metabolic rate, which means that while
searching for food rays continue to burn energy. If they use up
energy looking for food, but do not find any, they will lose
weight. To compensate for this loss of energy, it is essential
to provide adequate food. I cannot stress this enough. Hobbyists
sometimes tell me that they feed their rays three times weekly,
thinking that this is adequate. Stingrays should be fed at least
twice, and usually three times, daily. In spite of these
frequent feedings, rays will still constantly look for food
between feedings!
When feeding significant quantities of live feeder goldfish, it
is wise to add vitamin B1 to the feeder supply. Goldfish contain
the enzyme thiaminase, which destroys thiamin, or vitamin B1,
and this vitamin must be replenished. It should be your practice
to add one 50-mg tablet to each 500 gallons (1893 L) of water
every two weeks. You can add the tablets directly to the sump of
the wet-dry filter; or as an alternative, the tablets can be
added directly to the tank.