At the Oceanium in Rotterdam Zoo Blijdorp a new, large school of herring is now swimming among the barracudas, sharks, tarpons and other predator fish in the big shark tank.
The school is comprised of 2400 ‘imitation’ herring, not the real thing: these fish come from the Caribbean. In the wild, the imitation herring are prey for various predator fish, but they don’t get eaten immediately at Blijdorp because the large predators are well-fed. The expectation is that the school will slowly decrease in size as individual fish disappear into a large fish belly now and again, but that visitors should be able to enjoy watching them for at least a few years. And enjoy they do, as the school presents a fascinating spectacle.
The imitation herring school was introduced into the tank with care. First the animals were quarantined for a time, and then their container was suspended in the shark tank. During this period, the water in the container was refreshed with water from the shark tank to get the small fish used to its scents. The herring school also has the opportunity to shelter in a protected shallow zone of the tank.
The Diergaarde Blijdorp channel on YouTube features a short film showing the release of the herring into the tank.