Common Aquarium Sicknesses

Have you recently made changes in your aquarium or have brought new fish home?
Do you believe your fish may be sick?

The most common reason a fish may be sick is from parasites (internal or external). There is also fungal, bacterial or viral infections also.

It’s a good idea to have a basic understanding of the signs & symptoms for the common diseases so you know the best treatment pathway for your fish.

Read below on common diseases shown in tropical fish, and how you can try help treat them at home.

The first step we recommend is testing your water quality. Should you not have a master water testing kit at home, bring in a 40mL water sample into store for a FREE water testing and consultation.

Let’s dive in!

It’s imperative to ensure your fish have the right water quality for their species, and are introduced into your aquarium through correct acclimation processes. Without these, the fish as susceptible to stress and in result, illnesses.

Signs & Symptoms
This infection attacks the fish’s gills and skin, causing a grey colour to their skin and white spots (almost like they have salt all over them). Your fish will appear lethargic, weak and refusing food. They may rub their sides on the tank or spend their time at the top of the tank gulping for air.

Treatment for Ich
It’s important to read the labels of your medication bottles, as most will require you to remove any carbon from your filter (as this will absorb any medication you add to the water)

Common treatments for ich are medicated fish tanks with aquarium salt, potassium permanganate or copper sulfate. Here at Nick’s, we recommend Ichonex (a copper based product).

• Treat at the rate of 5mL per 40 litres on Žthe first day and on days 2 & 3 at 1/2 of the initial rate (2.5mL/40L).
• To maximize result, 1/2 the daily dosage, adding it to the tank twice (morning and night).

Important note: The copper component is more toxic at low pH, so keep pH above 7.5.

Raising the temperature by 2-3 degree celsius will also assist with shortening the life cycle of the parasite thereby targeting the affected stage of ich life cycle, more effectively.

Symptoms of Constipation

If your fish is constipated, you may notice a bloated abdomen. It’s imperative to address this as soon as possible, as constipation can cause them to develop swim bladder disease.

Treatment of Constipation
Like the treatment of constipation for humans, to treat fish constipation we increase their fiber in their diet, and you could also provide a de-wormer.
Another method to reduce constipation in fish is to dose your tank with 1 – 3 teaspoons (every 18 litres) of aquarium salt.

Note: The salt will act as a muscle relaxant which will help them pass faeces.

Signs & Symptoms: 

Common signs and symptoms include:

• Red spot on the body
• Ulcers on gills
• Enlarged eyes
• Swollen abdomen

Treatment of bacterial infections:
You can choose to use a quarantine tank to treat the fish, however before they’re returned the tank will need to be corrected and cleaned. You could always treat the tank they’re in, which will work as a preventative for any other fish in the tank too. 

To treat the bacterial infection, a medication we sell and often recommend are either of these treatments: Tri- sulfa tablets, Bactonex or Melafix. With all three options, removing carbon from your filter is required.



Tri-sulfa:
• Pre-dissolve tablets in a disposable cup before addition to the aquarium water.
• Use 1 tablet per 40 litres of aquarium water. In the case of severe infestation use at the rate of one tablet per 20 litres of aquarium water.

Bactonex:
• Use at water change time and when adding new fish.
• Use 10mL per 40 litres.
• Repeat after 5 days if necessary.

Melafix:
• Shake well, add 5ml per 190 litres of aquarium water
• Dose daily for 7 days, after 7 days make a 25% water change.
• Continue if necessary

Symptoms of Fungal Infections

Most common signs seen with fungal infections are a grey cotton-like growth on their skin, gills, fins and even around their eyes. This type of infection will cause damage to their internal organs.

Treatment of Fungal Infections

We would encourage checking your water parameters, and then doing a full tank clean. Depending on your species of fish, you may raise the temperature of the tank slightly as fungal infections will thrive in colder temperatures.

You can then use medication such as Aquasonic Fungonex.
• Add 5mL per 20 litres.
• Repeat treatment after 3 days if necessary.

Fungal infections can be prevented. To control mild fungus infections (or fungus on eggs), you can use the product methylene blue. As this product is not as strong as other medications, it is really only effective as a preventative method.

For preventative method, use 5mL per 20 Litres of aquarium water each day for 4 days for both freshwater and marine tanks.

Signs & Symptoms:
Swollen abdomen where the scales look like pinecones (See picture above)

•  Eyes swelling and buldging (or become sunken)
•  Loss of colour in gills
• Pale faeces
• Becoming lethargic
• Hovering near the top or bottom of aquarium

Treatment for Dropsy

Dropsy is a serious disease which in most cases leads to death in fish. A vet visit is encouraged. To try remedy at home in the meantime, it’s a good idea to first check your water parameters, and if you can remove any stress factors (such as the poor water quality, overcrowding, parasites). Ideally, a quarantine tank away from high traffic areas.

An antibacterial like melafix is recommended to help reduce stress, heal wounds and promote re-growth of any damaged fin rays and tissue.

Moving forward, monitor your fish and ensure to maintain best water quality.
Reduce any stressors you see in their tank.