How do I carry out a proper quarantine?

We decided to put all new fish in a quarantine tank in future as a preventive measure. How long should the quarantine last, and what do I have to consider? What (sera mycopur, sera baktopur...) should I use for treating, and how often?


about 4 weeks are recommended unless this period does not prolong due to possible disease outbreaks and the subsequent treatment. The fish are normally fed during this time.
The most important measure is regular, careful observation.

The aquarium size depends on the number and sizes of the fish you need to accommodate. The tank may be somewhat smaller than for permanent care, but you should of course not stock it too densely.

Aquarium maintenance (especially water changes) is carried out as usual, some hideaways are recommended for stress reduction.

Plants can be potted for easier maintenance.

Bottom gravel is not used unless there are fish living on/in the bottom in the quarantine tank (e.g. Corydoras catfish or Coolie loaches). It is easier to discover if the fish excrete intestinal worms etc. when there is no bottom gravel.
Whenever bottom gravel is required, a 0.5 - 1 cm (0.2 - 0.4 in.) layer of round-grained sand will do - except for bigger fish that burrow in the sand (spiny eels, bigger banjo catfish up to freshwater stingrays).

As long as the fish are apparently healthy you should not treat them at all, but only if there are distinct disease symptoms are visible. Choosing a treatment then depends on the diagnosis.

However, it is advisable to exchange small portions of water between quarantine and main tank in regular intervals [e.g. 200 ml (7 fl.oz.) every other day], in both directions.

The immune system of the fish you already have possibly does not know the bacteria or pathogen strains the new fish "brought along" and did not develop any defensive measures. This of course also applies vice versa: The new fish do not yet know the micro organism strains they will get in contact with.

The method of exchanging small amounts of water between the aquariums allows the fish to slowly become familiar with the accordingly unknown strains without being confronted with the "full dose" at once.

If no disease symptoms have occurred until then, or possible diseases have been completely cured and the fish behave and eat normally, they finally can move into their new home!

Best regards

sera GmbH
Dr. Bodo Schnell

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