Stingrays and electric rays are found in the superorder Batoidea, which is also home to skates, guitarfishes and sawfishes. Sometimes the term ray is used for all the members of Batoidea, but it is more commonly applied to the members of the order Rajiformes. Rajiformes contains skates, guitarfishes and so called “true rays”.
The rays are found in the following families:
- Dasyatidae (stingrays)
- Gymnuridae (butterfly rays)
- Hexatrygonidae (sixgill stingrays)
- Myliobatidae (eagle rays)
- Plesiobatidae (deepwater stingrays)
- Potamotrygonidae (river stingrays)
- Urolophidae (round rays)
Stingrays are probably the most famous of the rays. They inhabit marine and brackish waters along the coasts of the Atlantic, Pacific Ocean and Indian Ocean. Freshwater species are present in Asia, Africa and North America (Florida). The name stingray is derived from the razor-sharp cartilaginous spine that extends from the tail of the fish. The stingray produces are venom capable of breaking down and killing cells as well as provoke smooth-muscle contractions.
Keeping rays in the aquarium
Most rays are not recommended for aquarists since they grow to large or need the vastness of the ocean to thrive. There are however a few species that have been successfully kept in aquariums, such as Bluespotted stingray (Dasyatis kuhlii) and Bluespotted ribbontail ray (Taeniura lymma). Both are marine species and must be kept in a saltwater aquarium. Dasyatis kuhlii can reach a size of 70 cm (28 inches), while the maximum size for Taeniura lymma is 35 cm (14 inches). As you can see, both will need huge aquariums as they grow older.
If you want to keep rays in your aquarium you must provide them a suitable substrate, such as soft sand, since they like to burrow. Optimal water quality will also be required. When handling your rays you must be careful, since several species can deliver a venomous sting with their tail.
If you need to medicate the aquarium you cannot use copper based medicine because rays are very sensitive to copper. The copper will be absorbed by the cartilage and make the fish sick.
Keeping Bluespotted ribbontail ray (Taeniura lymma)
The Bluespotted ribbontail ray hails from the Indo-Pacific and needs a water temperature of 22-22.5 ºC (72-78 ºF) in the aquarium. The pH-value should be 8.1-8.4 and the specific gravity 1.020-1.025. The species is aggressive and venomous. It will spend most of its time close to the bottom or borrowed in the sand. Never use a coarse substrate in the aquarium because this will injure the ray and the wounds can easily become infected.
The Bluespotted ribbontail ray is known under several different names, including Bluespotted Stingray and Blue Dot Stingray. Its main body colouration is tan and the fish it decorated with beautiful blue dots. Unlike many other rays, this species does not give birth to live young; it is an egg layer.
The Bluespotted ribbontail ray is a carnivore and can for instance be feed fish, shrimp, scallops and squid in the aquarium. It can be hard to get it to eat when it has been moved to a new aquarium. You will have to be persistent and try to tickle its appetite by offering it freshwater ghost shrimp or small tidbits of well cleaned squid. It can also be a good idea to ask the previous keeper if your particular specimen has any favourite food. Once your Bluespotted ribbontail ray have started to eat it cannot be kept in the same aquarium as small fish and invertebrates because it will readily eat them.