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.
The symptoms may vary depending on the location of the ulcer: 1  Duodenal ulcers often cause a gnawing pain in the upper stomach area several hours after a meal, and patients can often relieve the pain by eating. 2  Many patients also have heartburn. 3  Gastric ulcers may cause a dull, aching pain, often right after a meal.