Affiliate Disclaimer:
FishKeepingAnswers.com is reader-supported. When you buy through links on our site we may earn a commission.
Unfortunately, no matter how much time and care we take looking after our fish, there are occasions when they become sick or attacked by a pest. In this article, I look at some of the most common pests and diseases to affect our fish and offer solutions based on my 30+ years in the hobby.
Some of the treatments I look at are based on medications available from your local fish store, whereas others are based on making a change in your aquarium to help your fish fight off the disease naturally.
Most Common Tropical Fish Pests and Diseases
In no particular order, the table below shows some of the most common pests and diseases that we can come across in our fish tanks, what the symptoms are, and a recommended treatment.
For more information on any of the specific pests or diseases, click on the name of that disease to be taken to a dedicated article I have written.
| Disease | Species Affected | Cause | Symptoms | Treatment |
|---|---|---|---|---|
| Ich (Whitespot) | All | Ichthyophthirius multifiliis parasite | Small white spots on fins and body | Use commercially available treatment such as Ich-X and raise the water temperature |
| Fin Rot | All | Bacterial | Fin edges becoming ragged and eroding | Remove fin nipping fish, improve water quality, treat with an anti-fungal treatment |
| Dropsy | All | Multiple different causes | Swollen, bloated body with scales sticking out (pinecone) | Treatment varies depending on the cause of the Dropsy |
| Internal Tapeworms | All | Internal parasite | Thin, lethargic fish, losing weight even though they are eating | Commercially available treatment for internal tapeworms and parasites such as Paracleanse |
| Columnaris (mouth fungus) | All | Flexibacter bacteria | White, cotton wool-like growth, especially around the mouth | Use commercially available treatments and improve water quality |
| Swim Bladder Disease | All | Bacterial infection or digestive issues | Inability to stay upright in the water | Treatment may be possible depending on the cause |
| Saprolegnia Fungus | All | Fungus | White, fur-like growths | Commercially available treatments |
| Malawi Bloat | African Cichlids, especially from Lake Malawi | Incorrect diet, stress, | Similar to Dropsy | Feeding a diet high in fiber |
| Hole-in-the-head | South American Cichlids | Hexamita parasite | Ulcer on the head-turning into a hole if left untreated | Commercially available treatments such as MetroPlex |
| Neon Tetra Disease | All | Pleistophora hyphessobryconis Parasite | Color loss, weight loss, curved spine | No known cure |
| Anchor Worms | All | Lernaea parasite | Parasite physically attached to the body | Physically remove parasite and treat to prevent secondary infection |
| Gill or Skin Flukes | All | Gyrodactylus and Dactylogyrus parasites | Difficulty breathing, fish rubbing body against decorations and tank sides | Commercially available treatments such as Hikari PraziPro |
| Velvet Disease | All | Oodinium parasite | Golden spots on the body, fish rubbing against decorations and tank glass | Commercially available treatments such as Cupramine |
| Piscine Tuberculosis | All | Mycobacterium marinum bacteria | Non-specific, sporadic fish deaths, susceptible to secondary infections | No treatments are currently available |
| Vibriosis | All | Vibro bacteria | Red fins and mouth, bulging eyes, lack of energy | No commercially available treatments |
| Pseudomoniasis | All | Pseudomonas bacteria | Fin erosion, lack of energy, body ulcers, death | |
| Iridovirus | Gouramis, Angelfish, Dwarf Cichlids | Virus | Loss of color, swelling, loss of appetite, lesions on the body | No known cure |
| Lymphocystis | All | Virus | Cauliflower like growths around the eye | No known treatment |
Further Reading
I have created a dedicated article discussing each of the pests and diseases above, detailing the symptoms, causes, treatment, and prevention for each disease.
Click on the name of each disease in the table above to be taken to that specific article.
