Fish Troubleshooting

We sell only health fish and pride ourselves that all our hard work is rewarded by the fantastic healthy selection of fish on offer at Tropical Fish By Post. With knowledgeable staff and detailed procedures our fish are among the best available. We take full responsibility of OUR fish.

We give all fishkeepers information and advice to ensure these fish thrive in their home aquariums. Although it seems obvious, once the fish leave our care, they are in your care. We can not know what actually happens to them. PLEASE TAKE RESPONSIBILITY OF YOUR FISH!


Sometimes a fish that should (according to the books) be compatible with the others in your tank, may get bullied by the fish in your tank.


Your aquarium is your fishes home. Any new additions may swim in areas of the tank that your fish have occupied, have claimed as their own and do not want to share with a stranger. This coupled with the stress of the move and their new surroundings makes them targets for bullying. Stress from transportation makes them weak.

In most cases the new fish will settle down, but occasionally the bullying is too much and they could die.

How can bullying be reduced?

As you introduce the new fish, move some rocks or plants around to change the landscape of the tank, or introduce some new plants. Your fish may take less attention of the new fish as they try to claim their new territory. You can always move everything back to where you like it a few days later when the new fish have settled.

Fit for purpose testing.

Is my water fit for the purpose of fish keeping?

Healthy fish may die if not looked after correctly. Fish need good water to thrive.

The following water test parameters must be met;

Tropical community                                  Coldwater                                Marine

Ammonia        0ppm                                    0ppm                                     0ppm

Nitrite              0-0.03ppm                           0ppm                                     0ppm

Nitrate             less than 20ppm               less than 40ppm                     less than 12.5ppm

PH                   6-7.0                                   7-8.3                                     8.1-8.3              

GH                  0- 20                                   10-25                                     20-35


Is tap water killing my fish!!!

Throughout the country, the quality of tap water varies. In some areas tap water is not safe to use for sensitive tropical fishes. Tap water is generally too hard with high pH values, which can be detrimental to the health of most tropical community fish.

Purified water can be used to ensure excellent water quality. Containers can be bought in store, filled with good RO (reverse osmosis).



What is new tank syndrome?

All new aquariums take upto 12 weeks to mature and settle down.

It is paramount that the aquarium is not overstocked or overfed.

Denitrifying good bacteria grow in the filtration which break down all waste pollutants caused naturally by the fish. At first there is not enough of these good bacteria to deal with all the waste caused from the fish. By introducing only a small number of fish in the first few weeks and by feeding minimal amounts of food, these waste pollutants will not build up to high levels that will harm the fish.

By ensuring the waste levels are low, more fish can be added.

Monitoring the waste pollutants (Ammonia, Nitite and Nitrate), you can ensure a safe healthy aquarium is maintained.

What are waste pollutants?

Waste pollutant are Ammonia, Nitrite and Nitrate, which are caused naturally by the fish. The most harmful is Ammonia. This Ammonia breaks down by denitrification to Nitrite, which is still toxic to the fish. This then breaks down to the less toxic Nitrate. Nitrate is less problematic and is not usually harmful at low levels.

All these pollutants can be tested for at home with a simple test kit.

The fish looked healthy in the shop, why has it died in my tank?

Water got too cold in transportation. Always take fish home immediately.

Water not ‘fit for purpose’.

Stress and bullying.

Whitespot or fungus. Once stressed and weak, fish are susceptible to getting parasites, fungus and bacteria that are always present in marine and freshwater aquariums. By treating the aquarium with a general tonic or a complete general treatment, this will prevent disease outbreaks. Recommend Waterlife Protozin and Interpet Liquisil.

Only the new fish died, all my others are OK? New fish must have been diseased?

Waste pollutants build up slowly and settled fish can, over time, get used to higher than normal levels of waste.

Introducing new fish that have been kept in water with no waste will be shocked by those high waste levels and potentially die.

Why do waste levels varying?

Over feeding.

Filter slowing down due to clogging. Clean filters more regularly and check its flowrate.

New tank syndrome.

How can I reduce stress to my fish?

Turn off the lights when introducing them.

Treat the water with Stresszyme/StressCoat.

Why did my fish get whitespot?

Once stressed and weak, fish are susceptible to getting parasites, fungus and bacteria that are always present in marine and freshwater aquariums. Whitespot manifests in the fishes gills which you will not notice. Once it is noticed on the body of the fish, you may encounter an outbreak which could spread to all your fish. By treating the aquarium with a general tonic or a complete general treatment, this will prevent disease outbreaks. Recommend Waterlife Protozin and Interpet Liquisil.

Introduction of Clown loach and Black Mollies are prone to whitespot and must be treated with anti whitespot to prevent outbreaks.


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