* Protozoa: Some protozoa, such as *Amoeba* and *Tetrahymena*, can ingest and digest archaea.
* Fungi: Some fungi, such as *Aspergillus* and *Penicillium*, can produce enzymes that break down the cell walls of archaea, allowing the fungi to absorb the nutrients inside.
* Viruses: Some viruses, known as archaeal viruses, can infect and kill archaea.
