The chytrid fungus batrachochytrium dendrobatidis is colonizing frogs across the globe causing massive mortality and even pushing some amphibian species to the brink of extinction. the batrachochytrium dendrobatidis-frog relationship can be considered

Parasitism

Explanation:

Batrachochytrium dendrobatidis is a parasitic chytrid fungus which is responsible for the declining population of amphibians in the rain forests of Panama and Australia.

The fungus grows on the keratinized layer of epidermis on amphibian skin and makes a thick covering of fungus on the amphibian's skin. So as amphibian's skin helps them to maintain the proper osmotic balance in the body so when a thick fungus grows on their skin they are not able to maintain the correct osmotic balance in their body which leads to amphibian death.

So as Batrachochytrium dendrobatidis is a parasitic fungus and gets its nutrition from the frog body and do not kill frog immediately as in predation therefore this relationship can be considered as parasitism.