Offshore, dolphins cover huge distances every day, up to 150 km, and dive to great depths. Even the biggest pool cannot offer such an opportunity.
Dolphinarium water contains a great amount of harmful chemical substances. Dolphins' skin suffers and their vision deteriorates, up to the case that a dolphin can lose its sight and get blind.
In the open sea, dolphins catch live fish for food, and from that fish they get fresh water required for their life.
In the dolphinarium, the animals' diet consists of dead fish, in which there is practically no water. And fresh clean water is given to them through a tube probe which is inserted into the animal's esophagus.
In the wild, dolphins do not jump through a hoop, do not ride people. These tricks are taught to them for the performances, the only purpose of which is to raise money for the owners of the show.