A  Bat Ray Gets a Bath

No one likes ticks. Least of all a fish.

That’s why Senior Aquarist Erin Lyman and her team give freshwater baths to our beautiful bat rays every eight weeks. It’s a concept any pet-owning person can understand. Of course, these aren’t technically ticks—they’re tiny, three-millimeter flatworms. But, just like ticks on a dog, they make life unbearable for bat rays, attaching to skin, eyes and gills. If ignored, they can create vision problems, infections and all manner of misery.

But after just four minutes in freshwater, the parasites fill with water (due to osmotic pressure), burst, and fall off. For a fish, it’s the best bath ever.

Where do they come from?

The Monterey Bay Habitats exhibit—like all the displays in the Aquarium’s Ocean’s Edge wing—takes in water from the bay. This connection to the open ocean is one of the reasons our exhibits look so natural. But while bay water brings in many things we want, like tiny plants and nutrients—it also brings in a few that we don’t—like flatworms.

In nature, bat rays (Myliobatis californica) can scrape off the tiny ticks naturally as they move along the seafloor. But in the busy environment of our exhibit, this doesn’t always happen. That’s when we intervene. A total of four people—two in the water, and two above—are needed to gently urge the 25-pound rays into a sling, lift them clear of the water, and place them in the freshwater bath. It’s all over in a few minutes. It’s a process we also use with our giant sea bass and other fish, and was pioneered at the Aquarium.

Over the years our aquarists have tried many different methods to treat the pesky parasites, including filtration, chemicals and removing them manually. They also supplement the ray’s diet with vitamins and live oysters to strengthen their immune systems. But when it comes to getting rid of the nasties, nothing works quite as well as a bath. Our two large rays have reached the ripe old age of 10, so we must be doing something right!

Learn more about bat rays.

Erin and her colleagues presented the technique at the International Elasmobranch Symposium at the Aquarium in early November, and her findings will eventually be part of a husbandry manual.



  1. taras-bulbasaur reblogged this from atenderofsycamoretrees
  2. atenderofsycamoretrees reblogged this from nangoat
  3. nangoat reblogged this from montereybayaquarium
  4. whenwillmyurlshowwhoiaminside reblogged this from montereybayaquarium
  5. ninijen05 reblogged this from xwintersummersx
  6. xwintersummersx reblogged this from montereybayaquarium
  7. jcpb123 reblogged this from coralsharks
  8. armchair-zoologist reblogged this from montereybayaquarium
  9. ejlh reblogged this from st-aurafina and added:
    I’ve been to the Monterey Bay Aquarium, and it’s fantastic. I could happily spend hours and hours watching their...
  10. st-aurafina reblogged this from montereybayaquarium
  11. silverspiral reblogged this from accioharo
  12. tophatviolet reblogged this from accioharo
  13. accioharo reblogged this from montereybayaquarium
  14. snakepgua reblogged this from montereybayaquarium
  15. barrelr reblogged this from contrapositivity
  16. pedrocatorres reblogged this from montereybayaquarium
  17. nicholasnotcage reblogged this from griseus
  18. subatomiccc reblogged this from montereybayaquarium
  19. skyfilledwithprettypeople reblogged this from thissummerheat
  20. thissummerheat reblogged this from montereybayaquarium and added:
    This is so freaking cool.

About me

The Monterey Bay Aquarium, perched on the edge of a world-famous coastline, is your window to the wonders of the ocean. It’s located on historic Cannery Row in Monterey and is open daily except Christmas Day.

For more information about our animals and exhibits, and to view our live web cams, please visit www.montereybayaquarium.org.

Hours of operation vary by season. Daily schedules and tickets are available on our website or by calling
(831) 648-4800.