Fish disease is a complex subject
It is often believed that fish are less complex than other animals, and therefore disease diagnosis is simpler. Unfortunately, this is one of the big fish keeping myths! The simple fact is that it is impossible to make a full and accurate diagnosis without carrying out a basic examination of both the fish and the water they live in.
A basic examination involves testing core water quality parameters, an assessment of physical condition including a microscopic examination of samples of mucus and gill, as well checking the system for cleanliness, filtration and stocking levels. In some cases, bacterial sampling and culture, virus screening and other advanced diagnostic techniques may be required.
Realistically, few fish keepers have the skill or equipment to carry out a proper examination. The usual approach is to make an educated guess, based purely on the clinical signs. However, the drawback with this approach is that most ‘symptoms’ such as lethargy, not eating, rubbing, flashing, redness, heavy respiration and lesions, can have several possible causes. Indeed, in many cases, fish will be suffering from more than one disease. So, without an examination even the most experienced fish keeper can only make a guess as to what the problem is! In most cases the guess will either be totally wrong or incomplete.
Ideally, when disease is suspected a proper examination should be carried out. After all, we wouldn’t simply guess what was wrong with the family cat or dog! The simple fact is that there is a far, far higher survival rate if fish disease is methodically diagnosed and treated. Other considerations are the savings made on inappropriate and unnecessary treatments as well as fish replacement costs.\