The protozoa Cryptocaryon irritans causes white spot disease, which is a common infection in saltwater aquariums. Because one parasite may create 1,000 offspring in only one generation, a system might soon become overwhelmed. This parasite, which replicates within gill tissue, is extremely hazardous to your fish. Once a diagnosis has been verified, proper therapy must be carefully implemented in order to completely remove it.
The major clinical indication of white spot illness is pinprick-size white spots on your fish's body, as the name implies. In lighter-colored fish, they can be difficult to spot and are readily mistaken with lymphocystis or fin ray fractures.
Causes of White Spot Disease in Saltwater Fish
Cryptocaryon irritans, a ciliated protozoan parasite, causes white spot disease in saltwater fish. Ichthyophthirius multifiliis, its freshwater twin, has the same life cycle and disease. Cryptocaryon irritans has a complex life cycle that includes a trophont, or feeding stage. This stage of the life cycle takes place in the gill tissue, resulting in damage and reduced respiratory performance. It's also the time when your fish's skin develops "white patches." The adult parasite leaves the host at the conclusion of the trophont stage and descends to the substrate, where it encysts into a tomont. The cyst breaks during internal cell division, releasing up to 1,000 free-swimming tomites, or theronts. Each tomite attaches to a fish and grows into a trophont, which may then encyst to generate 1,000 more offspring after eating, demonstrating how rapidly this parasite reproduces. Depending on the water temperature, the full life cycle can be completed in six to eleven days.
Diagnosis of White Spot Disease in Saltwater Fish
White spot illness is plainly evident on the body of the fish, although it might be mistaken for lymphocystis or fin ray fractures. A skin mucus scrape and gill biopsy will be performed by your veterinarian to confirm the diagnosis. These are best done on a fish that has been anesthetized. This will confirm the white spot illness or hint to a different diagnosis when inspected under a microscope.
Treatment of White Spot Disease in Saltwater Fish
It is crucial to recognize the intricate life cycle of white spot disease when treating it. The encysted stage of the biological cycle has no effective therapy! To kill the free-swimming tomite stage, you must provide repeated doses of medicine. The parasite's feeding and encysted phases are resistant to treatment. The length of your treatment will be determined by the temperature of your water. The parasite will finish its life cycle faster if the water is warmer. Do not, however, just raise the temperature to expedite the procedure. You may unintentionally stress your fish, weakening their immune system and making it easier for the parasite to infiltrate and kill them.
Not all over-the-counter remedies are created equal. They may employ various active chemicals and have various impacts on the occupants of your tank. Copper is one of the most often used treatment additives, however it is hazardous to invertebrates like crabs and corals. If you can remove the fish from the tank and treat them in a separate hospital tank, the white spot disease life cycle in the main aquarium will be disrupted since there will be no fish to host it. If you are unable to remove the fish and your aquarium contains corals, crabs, shrimp, or other invertebrates, you must pick an invertebrate-safe treatment.
Hyposalinity, or lowering the salinity of the water, does not necessitate the use of chemical additions, although it is not suitable for all fish and invertebrates. If you can remove sensitive fish or corals, you can treat the delicate fish with a different therapy. Your salinity must be below 16 ppt (16 mg/L) for at least three weeks to be effective against saltwater white spot.
If you are concerned about treating your fish correctly, discuss your treatment options with your veterinarian.
How to Prevent White Spot Disease in Saltwater Fish
The easiest way to avoid white spot illness in the first place is to keep it out of your aquarium. An effective quarantine technique in a separate tank with separate filtering equipment achieves this. A quarantine period of at least four weeks is advised. The fish can then be moved into the aquarium if they are healthy. It's far easier to treat the fish in a quarantine tank than it is to treat the main aquarium.