What condition is characterized by the inability of a female fish to release eggs?

The condition characterized by the inability of a female fish to release eggs is known as egg binding. This occurs when a female fish, despite having developed mature eggs, is unable to spawn properly. Several factors can contribute to egg binding, including environmental stressors, improper water conditions, or physical abnormalities within the fish. As a result, the eggs can become lodged within the reproductive tract or the fish may be unable to enter the spawning process due to health issues.

In contrast, fish lice refer to external parasites that attach to the skin, gills, or fins of fish, leading to irritation but not directly affecting egg release. Koi herpes virus is a viral infection that affects koi and common carp, leading to lesions and high mortality, but it does not specifically cause egg binding. Nitrite toxicity is a poisoning that affects fish due to high nitrite concentrations in water, impacting their overall health and potentially leading to various physiological issues, yet it does not specifically prevent egg release. Therefore, egg binding is accurately identified as the condition where a female fish cannot release eggs.