Ichthyophthirius multifiliis, also known as white spot disease, ick or Icky, is a common and highly contagious disease of freshwater aquarium fish caused by the protozoan parasite. It can affect any species of fish in which it can fit its entire body length, though it is most common in goldfish, rudds, and koi; some species of fish are less affected than others and some seem to be resistant.
In the aquarium hobby, there are few diseases more infamous than ichthyophthirius multifiliis, or ick as it is often called. Ichthyophthirius multifiliis are tiny, white, blood-sucking crustaceans that infect fish and cause intense irritation that typically leads to death unless treated quickly with medications such as maracide or malachite green.
At some point in their life, every aquarist will have to deal with ichthyophthirius multifiliis, or white spot disease as it’s better known. This protozoan parasite is the most common aquarium disease and has been plaguing fish keepers since the hobby began!
Read on to find out how to recognize and treat this common and persistent infection.
Why is this disease so common?
This disease is so common because ich is nearly impossible to get rid of once your tank has been infected. It doesn’t matter how clean you keep your tank, or what fish you put in it, chances are that sooner or later one of them will become infected. After all, as many as 30 different species of fish can be carriers of white spot disease! Although not fatal to its carriers, white spot disease will cause extreme stress to your poor fishes and they may eventually die from it.
The best thing you can do when trying to cure your fishes with this disease is to add salt into their tanks (even though it will kill most of them). When treating ich, NEVER add medication without doing a 50% water change first; otherwise, they probably won’t work properly on removing symptoms since most medication used for treating ick targets surface cells only and leave behind harmful toxins.
Try something like a salt dip instead: Add 10 tablespoons of aquarium salt per 1 gallon into their tank for about 20 minutes.
Ichthyophthirius multifiliis under microscope
Ichthyophthirius multifiliis can be easily seen under a microscope as tiny moving dots in a fish body. This parasite is a protozoan flagellate and its size may vary from 0.1 to 2 micrometres (in diameter). When viewed from above with light microscope, it will appear as if there are two nuclei present within a single cell.
While infected fish seems normal at first sight, you’ll observe that his skin looks dull or rough and scales would seem sticky. Besides redness around an affected gill region, white dots color can also be recognized on young fishes.
Ichthyophthirius multifiliis life cycle
Ichthyophthirius multifiliis, otherwise known as ick, is a protozoan parasite that causes white spot disease in fish. This parasite’s lifecycle can last up to 120 days and involves 3 distinct life stages: egg, free-swimming larva, and cyst. Infection usually occurs via contact with other infected fish, unsanitary pond water, or through skin abrasions sustained while netting fish.
Ichthyophthirius multifiliis is a protozoan parasite (single-celled organism) that completes its life cycle in three stages: trophont, or feeding stage; tomite, or maturation stage; and cyst. Ich lives off of live fish tissue, usually on gills or fins, but also attacks dead tissues. The female lays eggs in batches of about 80 at a time.
This can happen many times during a host’s lifetime—possibly up to 18 times! Eggs fall to gravel bedding or are picked up by water currents. They hatch within about five days into motile, wormlike larval forms called tomites which have one job – swim around looking for another fish host. In order to survive under environmental conditions of low oxygen content, ichthyophthirius multifiliis produces proteins that make it more resistant than most other free-living amebas.
A tomite attaches itself to a new host and grows into a trophont, from which point it begins to feed. A few weeks later, it drops off and dies. After leaving its host, the trophont transforms once again from an aerobic organism back into an anaerobic one as it encysts itself. When you think white spot disease has gone away…it hasn’t. Just because you haven’t seen any signs for some time doesn’t mean you’re safe yet.
Because of these factors, it’s important to keep your aquarium clean and handle fish gently when moving them around. Besides causing skin lesions on its host, ick also spreads like wildfire if left untreated.
Ichthyophthirius multifiliis size
They are oval or pear-shaped and measures around 0.5-1.0 mm in size.
Ichthyophthirius multifiliis in fish
There are two types of parasites that affect fish: internal and external. The internal ones live inside their host, feeding on body fluids. External parasites attach themselves to their host and feed off its outer layer. Ich (the scientific name for Ick) is a parasite that falls under both categories.
It can be found on all types of aquarium fish, from goldfish to grouper to guppies. Ick has also been known to infect turtles and even tortoises. While ick looks like small grains of rice, it is actually much smaller than rice—mites range in size from 0.3-1mm long—and each mite has six legs as well as three pairs of claws!
How does my fish get ick?
Since Ichthyophthirius multifiliis is an external parasite, it enters your fish’s body through its skin in one of these two ways: (1) you add new fish to your tank and it carries ich with it; or (2) you have existing fish in your tank that is already infected.
Can humans get the Ich?
Yes, humans can get Ich too! But it’s not as common. Fish are more susceptible to contracting ich and therefore a lot of fish keepers will treat their tanks when they notice their fish have white spots. However, there is no harm in treating your tank even if you do not have an outbreak as it will ensure that your fish are kept in optimal conditions.
Can humans get sick from fish ich?
Ichthyophthirius multifiliis is a parasite that infects all freshwater fish species and can affect humans. Infection with ich can cause skin rashes on humans; however, other effects are rare. Individuals who have had open wounds in contact with infected water may experience itching or burning of their skin where they came into contact with water or where they rubbed against bedding; there are no reports of fever or malaise associated with ich infection in humans.
Sometimes, fish will have diseases that can be transmitted to humans. This is commonly a concern for goldfish and koi (carp) owners. However, white spot disease (WSD) is actually an external parasite infestation of fish, not a disease per se.
Ichthyophthirius multifiliis in humans
Ichthyophthirius multifiliis is a parasite that causes ich (short for Ichthyophthirius) in humans. Ich is, unfortunately, not a good nickname for your new disease-bearing pet, since it refers to something else entirely. The parasites are commonly called white spot disease because when they attach themselves to fish and fluke hosts, white spots appear on their bodies.
These spots are actually shed skin from each individual parasite. But before you launch into being a really tough guy about having ich — don’t — you have nothing to worry about. In fact, unless you’re an aquarium owner or work in a plant nursery, there’s zero chance you’ll come into contact with these parasites. They cannot be spread person-to-person and cannot survive out of water; as soon as they touch dry land they die instantly.
Ichthyophthirius multifiliis diagnosis
Fish with Ichthyophthirius multifiliis usually have whitish, raised sores on their skin and lose weight and become sluggish. The white spots may be difficult to see in fish that are dark-colored or large, such as koi, but are more obvious in small, colorful fish such as goldfish.
Among other symptoms are clamped fins and excessive mucus production. Fish may rub against objects in an attempt to remove sores.
Signs of external parasites may also be present, such as small brownish spots on the skin. The aquarium water will usually be clouded due to excrement and dead tissue.
How do you treat Ichthyophthirius multifiliis?
There are several treatment options when it comes to Ichtyophthirius multifiliis; however, prevention is always going to be your best defense. That’s why it’s important to quarantine any fish you purchase before introducing them into your aquarium.
One of the ways to treat Ich is by raising water temperatures in order for their life cycle to be accelerated and eventually kill them off.
However, that could also lead to stress on other fish as well as cost more money because of heating costs associated with a higher temperature environment. In some cases, ich can infect all or most of your fish causing them to fall ill and die quickly.
Those who have no idea what they are dealing with may mistake these dead bodies for signs that something else is wrong with their tank; when in reality, these animals have been infected by ich, which will likely spread if not treated quickly enough.
You can also treat ich with chemicals such as malachite green, formaldehyde, or copper sulfate but since most fish owners are against chemical treatments, focusing on how to prevent it rather than how to cure it will be a nugget.