Overfeeding is the number-one cause of high nitrate levels in aquariums. Overfed fish produce much more waste than normal, and when more food is given than they can take in, the uneaten food rots and produces even more wastes. Keeping too many fish in a tank also leads to problems with accumulated wastes.
Symptoms Caused By Esophageal Ulcer. One classic symptom is a dull or burning pain. It is common with all forms of peptic ulcers. The affected person may feel the pain radiating within the areas starting from the navel up to the breastbone.
Symptoms of ulcers in the upper small intestine (duodenal ulcers) and in the stomach (gastric ulcers) are similar, except for when pain occurs. 1  Pain from a duodenal ulcer may occur several hours after you eat (when the stomach is empty) and may improve after you eat. Pain also may wake you in the middle of the night.