In what way is a flea sucking a dog's blood similar to commensalism?

A flea sucking a dog's blood isn't exactly commensalism, but there is something in common here--both are symbiotic relationships. When two organisms live alongside one another, they may establish a symbiotic relationship. When a flea sucks a dog's blood, this is an example of a parasitic symbiotic relationship. Parasites like fleas and worms thrive on the energy provided by a host organism while offering no benefits to the host and, more often than not, causing some amount of harm. Commensalism, on the other hand, is a relationship between two organisms that share a space without either being harmed. In fact, one of these organisms benefits from the relationship without any detriment to the other. An example of a commensal relationship would be that between a clown fish and an anemone. Anemones tend to sting organisms that come swimming or floating by, but clown fish are able to coat themselves in a protective slime. When a clown fish lives inside the tendrils of an anemone, it is protected from potential predators who don't want to be stung. The anemone is not harmed or helped by this relationship.