What is it?
Thankfully, most fish owners will never come across this disease. But when this disease occurs it has devastating consequences. It progresses slowly, often with little symptoms. The fish will continually more lethargic until it finally dies.
It is caused by a bacteria that attacks a fish's blood vessels. The bacteria slowly spread, causing hemorrhaging along the way, thus the name. Eventually the disease reaches the heart and other vital organs and the fish will die.
It is often brought about by poor water quality, as are many diseases. Parasitic infections may trigger the disease, but are not a direct cause. The fish may exhibit dropsy-like symptoms as body fluids leak into the abdomen, causing the fish to appear pine-cone like.
It is also often due to high ammonia levels, and for that reason is more common in goldfish. (I.e., goldfish produce a lot of waste and in turn water is more susceptible to high ammonia.) Water changes should be carried out regularly to help prevent this nasty disease.
It may not affect all fish in an aquarium, and often only affects fish with a wound or point of entry.
As well as a bacterial form of this disease, a viral form also exist. It is less common however.
Symptoms:
Streaks of blood in fins are often one of the first obvious signs. The may have red areas on their body and eyes as well. The fish will become lethargic, which increases in severity as time goes by.
If the condition is brought about by ammonia, ammonia poisoning symptoms may also appear. These include gasping at the surface and rapid breathing.
Cure:
Quick treatment is essential! Firstly check water parameters (pH should be 6.5 - 7.2 and ammonia should be 0). Fix these and progress to treatment. A broad spectrum anti-biotic should cure the problem, providing there has not been too much internal damage done. Medicated food may also help. Sadly, it may be too late and the fish may die regardless.
A small amount of aquarium salt added to the aquarium will help with stress and will help restore fluid levels to a normal level within the fishes body.
Remember, water quality is always extremely important- so always check that first as it is often the cause of disease in aquarium fish. When treating sick fish, try to put the least amount of stress on them as possible, as stress will hinder the heeling process. Another thing is to remember is that generally, a healthy fish is a happy fish.