Marine stickleback populations live and breed strictly in the ocean. Sea-run stickleback fish are. anadromous, meaning that they are born in fresh water, spend most of their lives in the ocean, and. return to fresh water to breed. Freshwater stickleback fish live entirely in fresh water.
Among patients with Crohn's disease, 4% will have an anal fissure as the first manifestation of their Crohn's disease, and half of all patients with Crohn's disease eventually will develop an anal ulceration that may look like a fissure.
During an exam, a doctor can also find out whether another condition may be causing the fissure. Having several fissures or having one or more in an area of the anus where fissures usually don't occur can be a sign of a more serious problem, such as inflammatory bowel disease or a weakened immune system.