Diseases and Treatment


Unfortunately like all other living things fish are prone to disease through parasites and infections and it is up to us as their keepers to identify and offer the correct treatment to give them the best chance of recovery. Naturally some fish are more tolerant than others but knowing what signs to look for can prove vital in the fishes survival. Hobbyists often don’t know what signs to look for and/or what treatment method to use and granted it is some kind of a learning curve but by gaining a little more knowledge about the infections that affect ornamental fish hopefully you can prevent and/or cure most symptoms.

If you are keeping African Cichlids in particular (a spare tank wouldn’t go a miss no matter what fish you are keeping) I would recommend setting up a “Hospital Tank” which can also be used as a quarantine tank and getting it cycled while you set up your main tank or soon after. More on the quarantine process here. Having a spare tank ready to hold fish will help you isolate sick fish which will:

  1. Reduce the chances of illness spreading to the other fish in the tank as some disease are easily transferred.
  2. Reduce the cost of treatment significantly because the dose of any treatment will be dependant on the volume of water being treated. A smaller hospital tank will require much less medication than your main display tank. (note: if your main tank is less than a 100Liters this probably doesn’t apply)
  3. Prevent further damage to the sick fish as other tanks mates may target them. Also in the event the fish dies in the hospital tank you would avoid the possibility of other tank mates consuming the body.
  4. Unless you are 100% sure what the illness is it is better to treat 1 ill fish in a small tank than put the wrong medication in your main tank.

While it is not an absolute necessity, if you have the space and resources to set up a smaller tank of even 60Liters (you may need a bigger one depending on your fish size) as your hospital tank it could help you in the long run. Other benefits of a spare tank are you could use it as a quarantine tank to make sure any fish are not carrying disease and parasites before introducing them into your display tank. Click here for more on the quarantine process. Another reason having a spare tank is good is if you are keeping aggressive fish they may target and beat one of the tank mates and by separating the victim you could treat it in the spare tank and give it the best chance of recovery. Below is a list of common illnesses and how to treat them.

Dropsy/Bloat/Malawi Bloat

Fish with Dropsy will often stop eating and appear lethargic as the first symptoms and develop swelling around the abdomen in the later stages of the illness causing the scales of the fish to stand on end due to the bloating. By the time the fish is showing swelling it is often too little too late and majority of fish will never recover making this a horrible illness due to the suffering and high fatality rate it brings. Dropsy is often not triggered on it’s own as a healthy fish will be able to fight it off, instead it was probably caused by other elements such as weakened  immune system caused by some other infection and/or poor water quality. The swelling is caused by the fish being unable to get rid of fluid in the body and thus it build up in the body.

African Cichlids are particularly prone to this disease hence it is also known as Malawi Bloat, it is extremely important to maintain water parameters and test your water regularly and to act fast if you notice any fish not eating, hiding more than before and/or acting lethargic as at this stage there is a higher chance of survival. As with most diseases it should really be something you try to prevent rather than treat with medication once the fish is showing symptoms; however, knowing what to do is important.

  • Look for signs of abnormal behaviour such as not eating, heavy breathing, lethargic or minimal movement. Visual signs will be swelling to the abdomen however this is in the latter stages.
  • Remove the fish to a hospital tank. The tank does not have to be fancy as long it is cycled, has a filter and heater (perhaps a small decoration so the fish feels safe). Remove carbon media from the filter while medicating.
  • Dropsy medication is readily available in most fish shops. Depending on which type you buy follow the instructions on the box. Some medication require water changes during the treatment period, this will be stated also.
  • In the case of African Cichlids you can also use aquarium salt to aid the treatment as the salt helps the fish fight off the disease. Most aquarium salts can be used as a PH buffer, general tonic and/or boost depending on how much you use. Follow the instructions on the box and use according to your need.
  • After the treatment has completed keep the fish in the hospital tank for a further 2 weeks to gain it’s strength and get it back to feeding normal and to be sure the fish has recovered fully before returning it to the main tank.

Ich/White Spot Disease

Credited with being one of the most common of the aquarium diseases Ich is another nightmare. Usually the fish are pretty good at fighting it off by themselves but stress and poor water parameters can trigger Ich. The disease can often be easily identified due to white spots spreading across the fishes body and gills as well as the fish trying to rub itself against the substrate and objects in the tank. Ich is actually more commonly present than you may think, most fish we keep would have been in contact with it through out their life.

The life cycle of Ich is highly temperature dependant and treatment includes using temperature to shorten it’s life cycle and get rid. If left without treatment this will cause the fish a very slow and eventual death. Some people leave the tank running at 27/28’C to prevent Ich in the first place which is fine if your fish type is tolerant to the slightly higher temperatures.

  • Identify the ill fish by looking for white spots on the body and/or gills. The fish will also try to rub against the substrate and tank objects if infected.
  • You don’t necessarily need a hospital tank to treat Ich as you are treating the tank rather than the fish.
  • Raise the temperature in the tank to 82’F (27’C-28’C) slowly over 2 days. Make sure the water is well oxygenated using air pumps and surface agitation as raised temperatures decrease oxygen in the water. At this temperature the life cycle of Ich is reduced to 4 days. Use aquarium salts and/or medication to help the fish fight of infection. Keep an eye on the fish during this treatment to see if any fish are struggling because of the changed water conditions. Wait for atlas 3days since the symptoms have disappeared before slowly returning the water temperature to the previous level. You could also raise the temperature slowly to 29-30’C and instead not use any salts and medication due to even less oxygen in the water. Again waiting till 3 days after symptoms have disappeared before slowly returning to normal temperatures

Fin Rot

This Disease although relatively easy to prevent is extremely difficult to deal with, it is very contagious and if 1 fish is showing symptoms chances it will or has already spread to the other tank inhabitants. It is fatal if not discovered early enough and medication has been known to have varying levels of effectiveness but medication is readily available as well as antibiotics to stop infection in the area of the rot. Fin rot is a fungal infection and regular tank maintenance, correct stock levels and generally clean water will go a long way to preventing this disease, however, newly introduced fish may carry the disease and thus spread it to your other fish. If you have the space and equipment to set up a quarantine tank then you can be much more confident that the new fish has no illnesses after the quarantine period of 2-4weeks. Click here for more on the quarantine process.

  • Identify the ill fish by looking for signs of fins appearing torn, bitten and/or rotting away. This can be tricky if you are keeping aggressive species such as African cichlids as they fight amongst themselves to establish a hierarchy, if you are keeping these fish then look for other signs such as if the fish is lethargic and/or discoloured in appearance somewhat.
  • because it’s highly contagious you may wish to treat the whole tank with fin rot medication. Alternatively you can remove the ill fish to a hospital tank and start treatment there. This will make life easier and treatment more effective because it will give you the chance to do thoroughly clean the tank and decorations. Clean some of the filter media too but be careful not to clean all the media as you will need your bacteria colony to reproduce.
  • Medication is readily available at local fish stores, try to get one with antibiotics in it to clear up any infection at the rot site.
  • Follow the instructions on the box of the medication and treat the tank accordingly. Keeping the tank water clean throughout this process is important so increase your water changes to 50% every 2days unless the medication has different instructions for water changes.
  • There are aquarium salts available which can be used as a general tonic in small amounts to help the fish fight off disease thus helping to prevent an outbreak. Follow the instructions on the box for as how much salt to use.

Hole in the head disease