The Calgary Rays

It’s easy to kill a fish

The below are links to articles about the recent Calgary Zoo Cow-Nose Sting Ray inquiry:

DailyHerald Tribune

CTV

The Globe and Mail

It’s easy to kill a fish. I don’t mean intentionally, but inadvertently. It is such an unnatural environment when they are held in captivity, living their life behind four glass walls, with so much that can falter in such a close-knit, small ecosystem.

Minute changes in water temperature, ph, hardness, deficiency of dissolved oxygen (allegedly in the sting rays case) and levels of elements can reek havoc among a community of aquarium fish. Not to mention keeping aggressive species together. Captive bred animals are hardier in their tank raised environments, adapting to changes with more ease than their wild caught brethren, though the chance for mishaps still remains high, especially with more sensitive species.

So, can I fault the Calgary Zoo for their recent loss of those beautiful cow-nosed sting rays (which I had the pleasure of viewing and interacting with at the Toronto Zoo – amazing creatures, full of intelligence and personality)? I’m not sure that I can find them fully at fault, as there are issues with keep fish in a captive environment that are sometimes beyond control (though I will not speak of the other losses that have also recently happened with some of their mammals).

So many factors must be taken into account when dealing with aquarium species. My husband has been involved with raising and breeding fish for more years than I can count. And he has seen his ups and downs with these water dwelling creatures.

Tanganyikan cichlids, namely the tropheus variety, can really shoot down your confidence when raising and breeding these African beauties. They need hard water, they need specific ph levels, nitrate/nitrite levels, acidity levels, and temperatures or they do not thrive. The levels fluctuate, and they become sick. A loss of a whole colony can happen overnight as they are extremely sensitive to the aquarium environment. No poisoning, or toxins involved, which was the original hypothesis on what happened to the rays. And this can happen with many other species of captive, aquarium raised fish.

We had an incidence with our Koi Angels, in a tank that housed many different types from tetras to discus and rainbows. Overnight, the Kois all died, including one in a separate tank. We have no idea why, as the other fish living with them were completely unscathed an thriving.

So, unknowingly, it is very easy to kill a fish. It does depend on the sensitivity of the species that you decide to raise. Each type is different, and some handle changes in environment much better than others. My hump-backed limas are a perfect example of a hardier species, as they thrive and breed in water that doesn’t get changed on a regular basis, and that fluctuates in levels frequently (most likely the nitrates/nitrites are higher than they should be). They are just a hardier fish. Sting rays, apparently, are not.

This is the same, regardless if the fish are salt water or fresh water. Some are more sensitive to what we think might be insignificant changes than others, and environments need to be closely monitored in order for the fish to thrive.

It truly is a huge loss to have so many of these sting rays loose their lives – if you’ve been able to interact with them, you will know they are unlike any fish you’ve been in contact with before.

So is the Calgary Zoo at fault? I suppose in the long run, even though unforeseen circumstances and changes can happen in an instant when keeping fish in a tank or other captive environment, they are to blame as they are the keepers of these elegant creatures, and the rays depend upon the zoo staff for survival.

I would like review the long term effects that the handling of these rays has on their health. Precautions are taken before the viewing public is allowed to enter the tank area, however, this is definitely not a fail-safe, and I can not see human handling being good for their health in any way.

I just hope in the future more diligent measures are taken to ensure that no more harm comes to these delightful, intelligent and personality filled sea dwellers. And I hope that the Calgary Zoo is able to overcome their recent tragic losses, and move forward for not just the benefit of the zoo, but for the benefit of the animals that they protect.