How to Discover and Combat Illness in Your Aquarium

It is estimated that at least 95% of aquarium ailments are environmental rather than pathogenic, that is, the result of something the aquarist has or has not done, rather than infectious causes. Unfortunately most aquarists find this fact unpalatable and choose to convince themselves otherwise, commonly making an already bad situation worse by misusing medications; often several at once or in rapid succession, in the hope of finding a cure for the mystery ‘disease’. Such chemical hotchpotches are likely to kill fish which might otherwise have recovered, or wipe out biological filtration and create an even worse environmental disaster.

If your fishes are unwell, then unless they have obvious symptoms of a pathogenic disease, assume that the problem lies in your water, and check that it is as it should be. Often all that is needed is an extra partial water change to reduce a raised nitrate level; even if the water tests as alright, it is astonishing how often a water change solves the problem.

aquarium illness How to Discover and Combat Illness in Your Aquarium

The infective agents of some diseases, such as costiasis, bacterial fin rot, and fungus, may be present in any water but affect only fishes weakened by environmental problems. In such cases medication is required, but unless the environmental problem is remedied too, the disease is likely to recur. In addition to poor water quality, incorrect water chemistry and stress can also make fish vulnerable to illness. Prevention is the best policy.


Nowadays there are excellent proprietary remedies for many diseases; equally there are some which purport to cure certain conditions but may not be as effective as they claim. Where we recommend proprietary remedies, it is likely that any reputable brand will work; where we mention prescription drugs, then assume the worst about aquarium remedies. If we say there is no effective medication, then believe us! Beware of ‘cure-all’ medicines, and never use any treatment unless you are quite sure what you are treating. Random dosing in the forlorn hope of a cure is pointless and dangerous.

Always follow the manufacturer’s instructions regarding dosage; never add a bit extra for luck, as that bit may be the difference between death for pathogens and death for fish. Always complete the course of treatment; some pathogens can be treated only at particular stages of their life cycle, necessitating repeated treatments over a suggested period.

Not all medications are suited for all fishes, and some arc specific to fresh or salt water. Some are lethal to marine invertebrates, and many harm plants and filter bacteria. If necessary, make use of a hospital tank.

Leave a Reply

Your email address will not be published. Required fields are marked *

Powered by WordPress | Maintained by: Expert How | Thanks to Mega HowTo