Marine or saltwater fish are more coveted than the freshwater ones. But, being an aquarist (fishkeeper) is not an easy task, as taking care of fish requires a lot of skill. Saltwater fish are prone to several health conditions and diseases. Marine Fish Diseases The diseases are caused due to several reasons. Some are caused due to an unhealthy environment, while others are caused by parasites like protozoa or worms. Marine Ich Marine ich is caused by a protozoan named Cryptocaryon irritans. This disease is easily identified and its symptoms include white spots on the skin, gills, and eyes of the fish. Other signs include difficulty in breathing and cloudy eyes. Stress and lack of maintenance is the main cause of marine ich in fish. One should remember that this disease is contagious and can be fatal. Therefore, if you notice these symptoms in a fish, you should immediately quarantine it. Medications containing copper are effective in treating marine ich at an early age. Marine velvet, another saltwater fish disease, is similar to marine ich. The symptoms are, however, different. In case of marine velvet, the spots are smaller, and even darker than those found in case of marine ich. However, the treatment for both the diseases is similar. Ammonia Poisoning As the name suggests, this disease is caused when the amount of ammonia in the water increases. The level of ammonia should be zero, as even a slight increase in it can cause poisoning in fish. When suffering from ammonia poisoning, the gills of the fish appear red or inflamed, and the fish try to come out of the water for air. Ammonia poisoning can be treated by changing the water and using chemical neutralizer to reduce the level of ammonia. Uronema Uronema disease is caused by a protozoan called Uronema marinum. When suffering from this disease, symptoms like external ulcers, shedding of the skin, and cloudy eyes are observed. Similarly, blood circulation is also impaired, which results in the death of the fish. The only treatment for Uronema is a regular freshwater dip (for 5 - 7 minutes) or formalin bath. As the protozoa cannot survive in freshwater, it helps the fish to recover quickly. Head and Lateral Line Erosion (Hole-in-the-Head) Nutrition deficiency, poor environment, and poor quality of water can lead to this disease. As the name suggests, symptoms involve development of small spots or holes in the head and along the lateral line of the body. If the disease is not treated quickly, it can result in death of the fish. Therefore, improving the environmental conditions, food and water quality is essential. For better results, you can even use vitamin supplements or vitamin enriched food. Bacterial Fin Rot Bacterial infection due to poor quality water or stress in fish gives rise to this disease. Erosion and rotting of fins is its classic symptom. Reddening and bleeding in fins and gills, loss of appetite, and lethargy are observed in the advanced stage. Antibiotics are effective in treating bacterial fin rot disease. On the other hand, having good quality water and controlling temperature parameters is essential to prevent the disease. On a concluding note, we observe that most of the fish diseases can be prevented by ensuring a good quality diet and water. Similarly, daily observance and minimized stress also proves effective in keeping the fish healthy and free of diseases.