NGC 5189, also known as the Rotten Fish Nebula, is a striking planetary nebula located about 3,000 light-years away in the constellation Musca. Its name comes from its unusual, fish-like shape, with twisted lobes resembling a decaying skeleton. Unlike many planetary nebulae, NGC 5189 has a complex, asymmetrical structure, possibly shaped by magnetic fields, rotation, or interactions with a companion star. This makes it one of the more intricate and visually captivating nebulae. The nebula is formed by the ejected outer layers of a dying star, now a hot white dwarf, which ionizes the surrounding gas, causing it to glow.

Despite its vast size of 2,000 light-years across, the Rotten Fish Nebula remains faint and requires telescopic observation. It resides in the Musca star-forming region, an area rich in young stars and gas, highlighting the contrast between the ongoing stellar activity around it and the aging star at its core. NGC 5189 provides valuable insights into the final stages of stellar evolution and the processes behind the formation of planetary nebulae.