Ich / White Spot
General signs include white spots, rubbing and rapid breathing. Quarantine and water-quality management help reduce risk.
Fin Rot
Frayed or receding fins may be associated with poor water quality, injury or secondary infection.
Fungal infections
Cotton-like growths can occur on damaged tissue or eggs, often secondarily.
Bacterial infections
Ulcers, hemorrhage, swelling and tissue damage can have multiple bacterial or non-bacterial causes.
Parasites
Flashing, weight loss, abnormal feces and respiratory signs can have several causes.
Swim bladder disorders
Buoyancy problems can be nutritional, environmental, infectious or anatomical.
Dropsy
Swelling and raised scales are a symptom complex, not one single disease.
Velvet
Dusty appearance, flashing and respiratory stress can occur; early identification matters.
Healthy aquarium basics
Quarantine
Separate new arrivals when practical.
Water quality
Monitor ammonia, nitrite, nitrate, temperature, pH and oxygen as appropriate.
Nutrition
Use a species-appropriate diet and avoid chronic overfeeding.
Stress reduction
Provide suitable space, cover and compatible tank mates.