Despite the best efforts of Calgary Zoo officials, 200 dead fish have been found in the lower pools at the entrance to the facility on Friday.

Officials say it is likely due to a contaminant in the water.

"We are conducting a full investigation to understand what caused the deaths. The necessary tanks have now been completely flushed and stabilized," officials said in a statement Wednesday.

Emergency protocols were put into place and hundreds of fish in other ponds were saved.

"We are undergoing advanced water testing at this time to further investigate the cause," officials said.