1. Ich also known as white spot disease (Ichthyophthirius multifiliis)
Ich is a small protozoan that is very common, fish infected will often start rubbing themselves on ornaments and against the gravel. Ich appears as small white spots on the fish, that make the fish appear as if they have been sprinkled with grains of salt all over their body.
Unfortunately, when it comes to ich, you will need to treat the entire tank. There are many treatments for ich available, one of the most popular amongst fish keepers being ICH-X by Hikari.
There are also more natural approaches, such as raising the temperature of your aquarium, and treating with aquarium salt, and soaking fish food in fresh garlic before feeding them.
Allicin, a chemical in garlic has the ability to eliminate parasites.
2. Fin, Tail, and Mouth Rot
If you notice what looks like frayed fins and or tails, your fish may be experiencing fin or mouth rot. With fin rot or mouth rot, fish can really look terrible. Just as it sounds, the mouth appears to be rotting away, often leaving the mouth looking like it is stuck open, and this can make eating very difficult for your fish. Fin and mouth rot are often caused by poor water conditions, or injured fish, which then leads to a bacteria infection. There are antibiotics and other treatments such as melafix, or bettafix, you can use as directed to treat your fish. I find often times just doing extra frequent (sometimes daily) water changes and a little bit of aquarium salt can do the trick in the less extreme cases.
In extreme cases you will need to treat the tank with antibiotics. A broad-spectrum antibiotic such as erythromycin is usually recommended for this.
3. Fungal infections
Fish that have a fungal infection tend to have a gray or white growth on their body or fins. The discoloration often appears as if there is cotton on your fish.
If left untreated the fungus will continue to eat away at the fish’s body. This can be sometimes caused by or lead to bacterial infections on your fish, that might also need to be treated as well. This infection, like fin rot, can also be caused by poor water conditions, older fish, or fish that have been injured.
With this, there are several treatments available, commonly used are pimafix for antifungal use, and melafix if there is a secondary bacterial infection.
In more severe cases of secondary bacterial infections, you may need to use antibiotics such as nitrofurazone or erythromycin.
Dropsy is often recognized by your fish having a bloated appearance and seeing protruding scales that almost give your fish a spiked look. This is usually caused by a bacterial infection of the kidneys, and this can often lead to renal failure.
Often this disease comes on in fish that are either already ill, older, or have been kept in poor water conditions for too long. Antibiotics and frequent water changes tend to be used for treating dropsy, but frequently, because of renal failure, this disease is often fatal.
The antibiotics recommended for treating dropsy are erythromycin or minocycline.
Also known as gold dust disease, fish experiencing this will often have a rust like appearance on their bodies. Fish will often become lethargic and begin to rub themselves on ornaments and gravel trying to break free of the parasite. You will also sometimes notice clamped fins and labored breathing.
A common treatment for velvet is shutting off the tank lights, raising the temperature in the tank, possibly even covering the tank to help keep light out. Copper based treatments can also be used to treat cases of velvet if used as directed.
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