How to prevent fish illness & stress

Ammonia and nitrite, created by waste in the tank, will cause stress if not broken down by a good biological filter.

For us it would be like living in poisonous air, our lungs would get sick and our skin might get sore.

Take good care of the filter and it will take good care of the tank. The filter breaks ammonia and nitrite down to less toxic nitrate which plants use to grow – high levels of nitrate can also stress sensitive fish but will be diluted when doing water changes.

Changes in temperature for too long will cause stress in tropical fish.

Temperatures should not stay too high (above 29°c) or too low (below 21°c) for any amount of time.

A good heater will keep the temperature at the safe level (24-25°c) for most species.

Quick changes in temperature can also be problem so make sure to match water temperatures when doing a water change and acclimatise fish when adding them to a new tank.

Unlike cats and dogs, fish don’t really like to be touched so only handle them if completely necessary. When are you netting or handling, take care as this is not only stressful but can damage their scales opening them up to infection.

Banging on the glass, loud noises and floor vibrations can all be a cause of stress. You should also avoid turning aquarium lights on and off too quickly or frequently.

Not all fish are going to be friends and territory battles, bullying or fighting over mates, can all occur in the aquarium.

Over stocking can also be an issue so you only select compatible types of fish and the optimum number for your tank to create a happy environment. 

High pH above 8.2 or low pH below 6 for your everyday aquarium will create stress.

The only way to find a pH issue is to regularly test the water and good maintenance will keep problems from starting.

Quick changes of more than 1.0 should be ruled out, especially take care during water changes and when adding fish to keep stability with old and new water

Only use cleaning products and décor designed specifically for aquarium use.

Never use detergents, polishes, aerosols (e.g. deodorants, air fresheners) or other toxic cleaners to clean the aquarium as these will pollute the water.

Even sprays and chemicals in the air can be drawn into the water through gaseous exchange and can enter the water causing harm. Avoid using strong products on, around or near the aquarium.

Fish use oxygen to breathe, just like we do, so when there is a lack of oxygen in their environment that can be very stressful.

Things like: poor water circulation; high temperatures; lots of organic waste; oily foods coating the water surface and some fish medications can also cause a lack of oxygen in your fish tank.

Good maintenance will help maintain oxygen levels and you can add aeration with an air pump or air stone. Adding aeration is really important in hot weather.