It is very common to see white spot diseases on koi or goldfish. The challenge with white spot diseases is figuring out which one it is and whether the specific disease your fish has is viral, parasitic or bacterial Viral diseases cannot be cured with any medication and either go away on their own or permanently affect the fish. Once your fish has been infected, it will carry the virus for life--even if it doesn't show symptoms. Bacterial and parasitic diseases, however, can be eradicated with the proper treatment. Here are 3 common white spot pond fish illnesses:
Ich: (parasitic) This is one of the most common fish diseases in both pond and aquarium waters. Luckily, it is easily curable and does no harm to the fish if treated early. If left untreated, it can can lead to death of the fish. Ich is very contagious, and spreads easily throughout the pond from one fish to another.
Ich looks like tiny white dots all over your fish, and as if someone has sprinkled salt on the fish. Ich parasites have a lifecycle of about 10 days, so it’s important to keep any treatment you do going for at least that long. A good tell-tale sign the fish has Ich aside from the white spots, is that you may notice your fish rubbing against surfaces in the pond in an attempt to scratch. The fish may swim funny or look lethargic, so be sure to act quickly.
Salt and warm water does a good job of curing Ich, but there are also many store-bought meds that will cure Ick quickly as well. I love personal quICK Cure. It typically stops Ich in 24-48 hours (Be warned this product is highly staining to hands so wear gloves and will turn you water blue for a few days—but it then clears up).
Carp Pox: (viral) This disease is unmistakeable because the white spots look like candle wax drippings on the fish. They are most common on the top part of the fish, particularly on the top of the head—but can appear anywhere.
Carp Pox is most commonly seen in the spring time (but there is also a cool water version you'll find in the fall). It may appear to “cure” in colder temps, but don't be fooled. The fish is not cured at all as the disease is viral--and as mentioned above viruses cannot be cured. Oftentimes, you will see fish pox just one summer and it never returns again; in other cases, the disease may return each spring when the water temps warms up again. Being a virus, there is no cure and the fish simply lives with the disease for the rest of its life. It rarely kills a fish, and the but is usually only disfiguring with the candle wax spots. Some people hate the fact that the fish appears this way and will humanely destroy it. However, there really is no reason to do so. The fish will eat and be lively just as it was before.
Pox comes into a pond because a new fish that has been exposed and was not properly quarantined has been introduced into your pond. Once that fish is in your pond, all your fish are now exposed, even if they never exhibit the white spots, but they are carriers nonetheless. Any fry born in the pond are also natural carriers. The only way to get rid of fish pox from your pond, is to humanely kill all the fish, clean the pond with a light bleach solution, throw out your filter materials and start up a fresh pond. Truly, however, fish can live perfect lifespans with pox, it is just important never to give away any of your fish or plants to another person, as you will pass the disease onto their pond. It is also a good reason not to take fish from a stranger's pond unless you know the pond very well.
Lymphocystis (viral): This virus shows itself as big, uneven bumps that look like grains of rice or rock salt. Every so often, there are so many bumps bunched up closely together that they appear like a small head of cauliflower (a.k.a. “cauliflower disease”). Lympho can look white, off-white or even have a pink hue. The disease can appear anywhere on the fish, but it is often seen on fins or tail tube.
Similar to Fish Pox, this disease hardly ever kills the fish, and the fish can live a perfectly normal life and behave normally. If the bumps cover the mouth area, it can make it hard for the fish to eat and it can die. As with any viral disease, the immune system is compromised. The fish is open to possible secondary infections that can cause death. So, it's super critical to keep a clean pond environment to prevent bacterias or parasites from affecting the fish and potentially causing it to die.
Just like Carp Pox, this disease is viral. It is not curable and all the fish in your pond are exposed whether they show the symptoms or not. Do not give away any fish or plants from a pond infected with Lymphocystitis. Just like Fish Pox, the disease can appear to go away and be cured and you may see no sign of the spots after a while, but remember that the fish will always be infected even if you don't see the tell-tale signs.
Some believe that quICK Cure "cures" lymphocystis with a 2-week round of use. There is no definitive study on this, but some people swear it is the case. You can read about this on the internet if you are so inclined. Even if your fish appears to have been cured, you should still assume will always be a carrier.
Finally, in order to prevent diseases, it is important to maintain a solid, weekly housekeeping regimen in your pond. Cleanliness wards off many parasites. Additionally, the importance of quarantining new fish cannot be overstated. Though the fish may look fine when purchased, it may take weeks or even months for a disease to show itself. Be wary of accepting re-homed fish unless you truly know the owner and their pond. Sometimes, free can bring on an unwelcome problem and kill your existing fish. It is best to buy fish from a breeder who you know well whenever possible.
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