Cortez Round Ray

 Quick Care Facts

• Care Level: Expert   • Temperament: Semi-aggressive   • Maximum Size: 14"
• Minimum Tank Size: 360 gallons   • Water Conditions: 68-78° F, dKH 8-12, pH 8.1-8.4, sg 1.020-1.025
• Diet: Carnivore   • Origin: Sea of Cortez, Eastern Pacific, Baja California
• Family: Urolophidae   • Species: Rays   • Aquarium Type: Fish Only

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The Cortez Round Ray is a member of the Urolophidae or Round Ray family, but can be found within the aquarium trade under a variety of common names including: Cortez Ray, Cortez Stingray, Spotted Round Stingray or Chocolate Chip Ray. Round rays are very similar to stingrays, as they both have an oval or near circular disc shape with pectoral fins that are continuous with the sides of the head. Cortez Round Rays have slender tails that are about half of the length of the disc, with large venomous spines.

While they are not overly aggressive, they are potentially dangerous as their venomous tail spines can inflict a painful and slow to recover wound. The Cortez Round Ray is found living in warm temperate waters off the Pacific coast of Mexico and Baja California, where they tend to inhabit shallow sandy areas near rock formations or reefs. The shallow coastal waters that the Cortez Ray inhabits are full of small crustaceans and mollusk for the rays to feed on and have rocky formations to provide the ray cover from larger predators.

Cortez Round Rays are born at approximately 5 inches in length and can grow to about 14 inches in length. The overall length of their body and tail combined can reach 14 to 16 inches in length, while the width of their disc typically reaches about 10 to 12 inches in diameter. Cortez Round Rays generally reach their adult size in about 2 to 3 years; however, they often grow more quickly in the aquarium environment where they receive regular feedings. The small size (for a ray) and overall hardiness of the Cortez Ray makes it suitable for large aquariums maintained by advanced aquarium hobbyists.

Stingrays need large aquariums with plenty of open sandy areas and small rocky formations in order to provide them areas to swim, hunt and seek shelter. While small specimens can be raised in smaller aquariums, adult Cortez Round Rays will need an aquarium with a foot print of approximately 8 feet by 3 feet in order to give them the necessary swimming room they need. Hobbyists should only purchase Cortez Rays if they have a large 350+ gallon aquarium available to house the species as an adult.

It is recommended that ray aquariums have a deep sandy substrate in order to replicate the natural habitat and feeding patterns of the ray. The natural behavior of burying themselves and searching for food in the sand will help keep the sand bed turned, which helps prevent dead spots from decaying food matter. Strong water flow, mechanical and biological filtration are required to maintain the overall water quality of the aquarium. Large bodied fish like stingrays and sharks produce large bio-loads that require strong filtration systems to be handled properly.

It is highly recommended that the stingray aquarium have a large sump, protein skimmer and plenty of water flow to keep dissolved oxygen levels high. Lastly stingray and shark aquariums should be well covered to prevent these strong fish from accidentally escaping from the aquarium.

Like their shark cousins, stingrays are not suitable for all aquarium environments or tank mates. Cortez Round Rays should be kept in FOWLR aquariums with compatible fish tank mates. Many fish species like Angelfish and Triggerfish will pick at the stingray, which can cause damage and stress. Generally speaking fish that pick at the rocks or have sharp teeth are not usually well suited for shark and ray aquariums.

Since the Cortez Ray feeds primarily on mollusks and crustaceans in the wild, they should not be kept with these species within the aquarium unless they are intended as food. They will not generally bother sessile invertebrates like corals or clams, but their large size and swimming motion makes them too destructive to be kept in most reef aquarium environments.

Cortez Round Rays are active daytime feeders that forage in the sand for a wide range of mollusks, crustaceans, shrimp, crabs and worms. They can be fed a wide range of marine meaty foods including: frozen feeder fish, silver sides, raw shrimp, clams, squid, mussels and other similar marine based meaty foods. Hobbyists should experiment with both the amount of food being fed and the frequency of feedings to determine the ideal balance between nutritional health and controlled growth rate. Initial feedings 3 times a week an amount of food the ray will consume within 5 minutes is a good starting point. Monitor the girth, overall health and growth rate of the ray to adjust the feeding regimen accordingly.

Caution - This species is Venomous, and should be handled accordingly as these animals have an extremely painful sting. If you do get stung immediately soak it in hot water and call a doctor!