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Why my Aquarium Fish Died? Quarantine

Updated: Feb 1, 2023

Beginner Aquarists are not aware of the importance of quarantining new fish. The Article will throw some light on our experience and the result of not quarantining new fish.

Our experience of not quarantining new Fish

Just two weeks back I had brought mollies from a local vendor and was very happy. I just gave them a dip in medicated water for around 4 hours. The idea was to get rid of any parasites lingering on the fish. quick bath dip is not a good idea.

LFS (Local Fish Shop) deals with lots of variety of fish. Quite often the fish is not kept in clean waters. Poor maintenance, Stress leads to ICH and other diseases. they do not quarantine properly before selling as they are more interested in making a quick buck. It is sad but true. Seldom, you will find proper procedures followed for selling new fish which has arrived at the LFS.

ICH caused my fish to die

You must always follow proper procedures when bringing new fish to your aquarium. At least quarantine new fish for a minimum period of 2-3 weeks before introducing them to your aquarium. Some professionals quarantine their fish for at least 2 to 3 months.

I brought new fish to be added to my planted aquarium locally. The mistake I did was not quarantining the fish due to the lack of a decent tank. After a week to 10 days, I noticed white spots on my discus and also my clown loach. I was very devastated to see this happening to my planted tank of 3 years due to my fault. To my good luck, I trust seachem Paraguard in treating Ich. With my temperature raised to 33 degrees, I started my treatment. I lost a few loaches and a betta while treating the ICH. It was a learning for me as Seachem Paraguard is a little harsh on invertebrates. scales' fish. Never dose as per the prescribed dosage on paraguard, just go halfway with it. If it says 5ml go with 2.5 ml at the beginning if you have scales fish or invertebrates.

I could get rid of ich on Discus within 3 days of treatment with Seachem Paraguard with raised temperature to 33 degrees. The infection was really bad. Seachem has got a medicinal product called metroplex which can be given to invertebrates mixed with food and is safe while treating Ich.

Tip:- Always treat the entire tank when faced with ICH. There is no point in removing the infected fish separately for treatment. Ich parasites always linger on driftwood, substrate, etc, Always disturb the sand during the treatment as they should not linger deep into the sand. The parasite will die if they

do not have any host. The whole tank needs to be treated at least for 14 days. Usually, the parasite will leave the host within 3 to 4 days of treatment. But it's always good to keep up the game with ICH.

I was also advised to switch off the lights while treating ICH in a planted tank and it worked well.

The idea of this blog is to highlight the importance of quarantining your fish before introducing it to your established aquarium. Never trust your LFS. A small precaution can go a long way. You can either use Seachem Paraguard or Seachem Stress guard for quarantine purposes. Latter is better to deal with stress or quarantining purpose.

Please note that Seachem is not paying me to talk about their products. I wish they had drawn a cheque for doing it. I am writing about them here because we have used the product at our store and found it effective.

Setting up the Quarantine Tank

A suitable size Aquarium

Sometimes there is always a constraint in space in most Urban houses. First of all getting permission from parents or elders to bring an aquarium is a big ask. Then, to ask to bring another Quarantine tank is like asking for the moon for lots of others. But, believe me, this process will solve lots of problems in the main tank. Just go in for a small tank of 2ft length x 1-foot depth x 1.5 height. This will suffice even when you want to quarantine your fish when it is sick. So the advantage of having a spare tank solves two purposes 1) quarantining new fish and 2)when fish in the main tank is not well and you need to isolate it.

We set up the entire system for quarantining the fish at least 2 weeks before the arrival of new fish. Additionally, we add nitrifying bacteria to the tank and we add Stability from Seachem. You can use other competing products from Easy life - Easy start. or even API products. We do this exercise because we like to stabilize the quarantine tank from sudden shocks to the newly brought in fish.

Why Stressguard? Because it helps in healing any wounds that occurred during the transportation of the fish to your home. You can reduce primary and secondary infections. The other advantage of this product is that it will not increase or decrease the pH level in the Aquarium. Use the product for at least 14 days when you bring in the fish. De-stress your fish from a long journey. The filtration needs to be on at all times. After 24 hours, you can repeat the process of adding Stressguard (if you come across any open wounds) and Paraguard can be used to Eradicate ectoparasites, Fungal, and bacterial lesions. If you find that there are no open wounds on the fish and the fish was brought by you from the nearest store then you can use Seachem Paraguard straight away for 12-14 days. Dose accordingly as per the instructions specified on the bottle.


What we do is have a basic sponge filter or you can use any internal filter suitable for the tank. But, We highly recommend using the sponge filter, A very good mechanical filter that helps beneficial bacteria to grow into it. At least give a rinse to the sponge filter once a week using the same water from the tank when used in the quarantine tank. Do not wash the sponge filter using the tap water.


We would recommend the heater to be used only if there is a dip in the temperature. Or you can raise it to just 1-2 degrees more while using Parguard. Use a good heater that will work and not kill your fish. There are lots of these Chinese heaters which you need to be concerned about. We encountered a problem one day where we lost most of our fish due to the faulty running of the heater which increased the temperature to more than 5 degrees automatically. Since then, we test the heaters for more than a week to be on the safer side. Investment into a good quality heater will go a long way in helping the fish to recover from sickness in the case of Ich. (the most common disease in a fish tank, especially with the tetra)


I get this question most of the time from beginners.

Never use any decoratives in the Quarantine tank whatsoever because quarantine tanks are used for quarantining purposes and not for display purposes. Keep the tank bare bottom.

Feeding the fish during the Quarantine Process

Feed the new fish after 2 days in a quarantine tank in small quantity. Any food that is not eaten needs to be removed by siphoning method; because any food uneaten will spike the ammonia in the tank.

Water Changes during Quarantine

Please do the water changes at least once a week. Water changes will remove the disease and possibly get rid of re-infection. do around 40% water changes.

Conclusion and Tip for after use of quarantine tank:-

Quarantining new fish is always a good practice. keep an eye on the fish every day. It's better safe than be sorry. Don't let the water from the store get into the quarantine tank.

After quarantining new fish for at least 2 to 3 weeks, your fish is now ready to go into the main tank.

  • Check the water temperature of both tanks (the main and the quarantine tanks).

  • Don't put any quarantine tank water into the main tank.

  • Transfer the fish safely with the help of the net.

  • Wash the quarantine tank, and wash all the equipment used during the process of quarantining. Some of them give a warm water wash and also use rock salt to clean the tank.

  • Do not use any soap or even detergents to wash the equipment or the tank.

Please subscribe to our newsletter and spread the word around to other beginners that we are there to help them startup their journey into this fascinating world of aquariums. Let them be part of the exciting journey into this fascinating world of Aquatic life.

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Author: Sunil Dcosta Proprietor of also


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