Costia necatrix

9.9

A tiny animal that lives on fish and often kills them

noun

Specialized

: Costia necatrix

The presence of Costia necatrix in the aquarium led to an outbreak of costiasis among the fish.

Examples

Veterinarians identified Costia necatrix as the cause of the rapid decline in the carp population.
Routine screening for Costia necatrix can help prevent deadly infections in ornamental fish farms.
The fish were infected with Costia necatrix.
Is Costia necatrix responsible for the outbreak?
Routine screening for Costia necatrix can help prevent deadly infections in ornamental fish farms.
The presence of Costia necatrix in the aquarium led to an outbreak of costiasis among the fish.
Veterinarians identified Costia necatrix as the cause of the rapid decline in the carp population.

Surface Forms

Costia necatrix singular

Morphology

Costia + necatrix

This is a scientific Latin binomial: 'Costia' identifies a genus of fish-infecting protozoans and the second element 'necatrix' conveys an agentive/death-related sense (nec- = kill). If a learner knew both constituent meanings and recognized taxonomic naming, they could infer a deadly parasite, but the second element is not an ordinary English word and requires specialised/Latin knowledge, so the link is only partially predictable.

Etymology

Costia necatrix may come from the way scientists named the tiny parasite: the first part Costia is the group name scientists gave it and the second part necatrix comes from the Latin word for 'killer'. So, because this parasite often kills fish, the name helps you remember it is a deadly fish parasite.