As soon as the fish are introduced to your tank, you must be alert straight away to prevent any illnesses. You will probably be looking in you new aquarium, thinking how good it is, but make sure that there are no problems as well .
Check and observe the fish: Look for problems with the skin, which are obviously the most important, where an infection can arise. Make a roll call for all of your fish, because if a fish is ill he will more than likely hide. He may then die there, and if the tank has a lot of hiding places, may never be found. Then he will just be polluting the tank, and get him as soon as possible.

Prevent any diseases: Its not always easy to cure an illness, so its better to prevent the whole thing. Tough, but if you keep a vigil you may find a small problem with a fish, diagnose it and then treat it, the problem is prevented.
The good health of your fish is very dependant on their enviroment - poor water condition (and I can tell you to start with my water was toxic to say the least), stress or incorrect feeding can lead to illness.

Example of a Healthy Fish



  • No fungal infection around the mouth, no erosion.
  • No "Pop-eye" (no bulging) eyes are clear.
  • Scales are in good condition; scales are flat aqainst the body.
  • No signs of erosion; fins are not clamped against the body.
  • No signs of disease; no spots, ulcers, haemorrhaging, or any mucus/slime around the body.
  • Faeces is in good conditions; not stringy, good in terms of recent diet.
  • Belly is not bloated; it is slightly convex, or flat.
  • Gills are not flared; (Unless the fish is diplaying for breeding or aggresion purposes). No worms, or mucus around the gills. Normal respiration rate.


Maintaining a healthy aquarium is a key factor in prevention of illness to the fish. These points should be considered:

  • Quarantine:All fishes must travel quite a bit before they reach your tank. And the longest "stopover" will be the pet shop. There should be a quarantine area there, and I would be suprised if there wasn't one. So I if you can (if you've got enough funds) use a quarantine tank to hold suspect fish there for a while, it could save the others.
  • Stress:Stress is a big factor if you want to keep your fish healthy. I mean I used to get stressed with my aquarium, let alone the poor fish themselves. The fish may well fall victim to a disease to which it is normally immunune. So you have got to reduce stress whenever you can, like handling the fish etc.
  • Vibration:Fishes will get stressed if the tank is tapped on the window, so don't encourage any kids to do so. Watch out for your Hi-fi as well, because I dont think fish will appreciate any Drum 'n bass.
  • Water quality: Try to keep the water clean and fresh. Don't forget to clean the filter, because it will clog up. Make water changes, conditioned fresh water will help the fish and the overall toxicity in the tank. I use a 20% partial change, because the nitrate levels are within the safety limits of my tank. It will be much better if you have a hose (I use a gravel vacuum cleaner) and a marked bucket, it's much easier for you and your fish.


Contributed by notcatfish.com