Pet Fish Guide
Pet Fish Article
Saltwater Fish Diseases
from: PetSpectacle.comBlack Spot Disease
Black spot disease is a parasitic infection. The parasites feed on the fish. The parasites move freely over the fish and appear as black spots on the skin. Black spot disease is most commonly seen in tangs, butterflies, surgeonfish, and angelfish. Affected fish scratch against objects. Signs of infection include lethargy, loss of appetite, loss of color, and rapid respiration. Secondary infections caused by bacteria may occur in damaged tissue. An outbreak of black spot disease often occurs after the introduction of an affected fish into the tank. Black spot disease is easily treated with commercially available parasitic medications.
Velvet Disease
Velvet disease is a parasitic infection. The disease is caused by the Piscinoodinium (or Oodinium) protozoan. In the free-swimming stage of the life cycle, this parasite will swim around looking for a host, which in this case is a fish. The parasite attaches to the fish and feeds off the fish. The parasite forms a cyst on the fish. Eventually this cyst releases free-swimming parasites (offspring of the original parasite) into the tank. The parasites cause small yellowish cysts to develop on the body and fns of the fish. The affected fish will swim with its fins close to its body. The parasites irritate the skin, and the affected fish will rub against objects in the aquarium. If the parasites are attached to the gills, the fish will exhibit rapid breathing. The fish may stay near the surface of the water and gasp for air. The Piscinoodinium protozoan contains chlorophyll and for this reason is also considered to be an alga. As the chlorophyll needs light, darkening the tank may help kill the parasites. This parasitic infection can be treated with a copper sulfate solution. A copper sulfate solution manufactured for the treatment of velvet disease can be put directly into the tank. However, copper sulfate will also kill the inhabitants of the live rock. Therefore, it may be best to treat the fish in a quarantine tank. It is likely that more than one fish will be infected.
White Spot Disease (Ich)
White spot disease in freshwater and saltwater tropical fish is caused by different organisms. In saltwater fish, white spot disease is caused by the Cryptocaryon irritans protozoan. Affected fish are covered with small white spots. The infestation may be mild at first but become severe. Affected fish scratch against objects in the aquarium. Other symptoms include loss of appetite, loss of color, and listlessness. Although the disease responds well to treatment, untreated the disease can be devastating to a tank. In the free-swimming part of the life cycle, the organisms (called tomites) attach to the skin and gills of the fish. They then burrow into the tissue and feed on the fish. The tomites eventually become encysted. The cysts may either remain in the fish's body or drop to the substrate. When the cysts rupture, tomites are released and start the process again. Copper is useful in killing the organisms in the free-swimming stage but does not kill the encysted organisms. It is recommended that affected fish be treated by means of freshwater baths and formalin baths and be kept in a quarantine tank. To prevent reinfestation, the aquarium must be kept empty of fish for a period of 4 weeks until the parasites die for lack of hosts. The aquarium can be treated with various products to speed up the process.