The Rotten Fish Nebula

LDN 1251, nicknamed the Rotten Fish Nebula, is a dark molecular cloud, site of stellar formation, listed in Beverly Lynds' Catalogue of Dark Nebulae and projected in the constellation Cepheus. It belongs to the Cepheus Flare complex of dark clouds — a vast region above the galactic plane known for low-mass stellar formation.

Its distance is about 1,000 light-years, consistent with modern studies that place the cloud at ~340 parsecs (≈1,100 ly); popular astronomy syntheses (e.g. NASA's APOD) round to ~1,000 ly.

Physically, LDN 1251 contains dense dust and gas that occult stellar light from the background at visible wavelengths, while active stellar formation inside the cloud produces Herbig—Haro (HH) objects — small shock-excited zones caused by protostellar outflows. These HH knots are specifically reported in professional and public datasets for this object.