Fish Disease Diagnosis
Fish Disease Treatments
Ponds, Aquaria & Filtration

Fish disease treatments

Treatments home page

Fish disease treatments should be straightforward provided that the problem has been accurately diagnosed at an early stage. However, it is very important to bear in mind that many fish are killed every year by the improper use of  medications. 

Disease treatments

an overview of how treatments work, why they often don't work and why they sometimes kill fish.

Disease treatment basics

When you have fish health problems, this guide details the steps to take, and what to do if it isn't possible to make a definitive diagnosis.


are an important treatment option against bacterial diseases if they are used properly.

Injecting antibiotics

gives the best results against bacterial infections  - especially when dealing with severe cases.

Antibiotic baths

and dips are not generally as effective as antibiotics given by injection. Baths and dips may however, be useful for surface infections.


Effective treatment against anchor worm (Lernaea) and possibly fish lice (Argulus)

Medicated food

is a useful option for treating bacterial disease, but it does have some disadvantages.

Sample downloadTopical treatments

can be very effective against bacterial diseases - especially when used in conjunction with antibiotics


Can be tricky to use - but is effective against some parasites - it can also assist in gill problems. 


  a  treatment for marine parasites.

Malachite green and formalin

an all-round anti-parasite treatment, especially good for white spot. 


the "bad boy" of treatments - but the best treatment for the "difficult" parasites such as Argulus.

Potassium permanganate

an effective treatment against many parasites, especially Trichodina. Can be useful for bacterial problems and disinfecting nets etc. 

Quaternary ammonium compounds: (QACs)

useful for gill disease - as it acts as a mild disinfectant with detergent action to remove debris.


The fish keeper's standby for parasites, gill congestion and osmoregulation problems. It's safe, and cheap

Using  "medications"

  • If possible, make a definite diagnosis rather than a presumption or guess.  This enables specific targeting of both the problem and cause. Follow the diagnosis guide
  • Check, double check and get someone else to check if you are not 100% sure of the volume of the pond or tank.
  • If there are signs of distress remove the "patients" or rapidly dilute the treated water
  • It is always advisable to carry out a follow-up examination to ensure the effectiveness of the medication and if necessary switch to another.
"Koi Health & Disease" by Dr. Erik Johnson DVM is 200+ pages from Fish Health Practice - Readable by Beginners and delivered overnight from

Fish disease problems? Need some help? The help pages take you through the basics of the 'fish health work-up' diagnosis method and basic fish disease treatment methods.

90% of all health problems and fish deaths are caused by poor fish keeping! The key pages are essential reading for all beginners and intermediates who are serious about disease prevention.


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What if you could just get "Here's what to treat with." and no advice or education?

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Expanded Content by Dr. Erik Johnson, and Used with Permission; Frank Prince-Iles ©2009 All Rights Reserved