Gnathiids and other external parasites are such a threat on coral reefs that cleaner fish have developed a niche eating the parasites of larger fish at cleaner stations. Much of Grutter’s ...

There is the Banggai cardinal fish, found only in Indonesia, which keeps its eggs and newly hatched babies in its mouth for two weeks. Then, there are gruesome parasites, his latest obsession.

Cichlid fish, particularly those found in the East African Great Lakes, are known for their remarkable diversity and evolutionary adaptations. This diversity extends to their parasites ...