How to set up a hospital aquarium

This page is part of our betta disease and illness section.

We also have a handy Betta Illness Photo Guide that we send out to members of our email list. The guide includes the key points about betta illness and extra photos of symptoms.

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A hospital aquarium is mentioned throughout our betta illness content; if you’re a betta owner, it’s useful to know how to set one up in case your betta does become sick. In this article we’ll talk you through how to set up a hospital aquarium.

Why use a hospital aquarium?

A hospital aquarium is an ideal environment to house your fish in should it become sick. Sometimes it’s good to transfer your betta to a hospital aquarium even if you don’t need to dose it with medication. If your betta is not alone in its original aquarium, it will give him or her some privacy in which the fish can amend stress free.

Also, certain types of heavy medication can affect the aquarium cycle. You wouldn’t want to damage the rest of the aquarium with heavy medication. That being said, heavy medication should only be used in extreme cases of illness.

Furthermore, a hospital aquarium may be necessary to ensure that the medication is not filtered out before it is effective. Depending on the type of filter in your aquarium, the medication may be removed from the water (especially if you have a carbon filter), rendering it ineffective to the fish! Placing the betta in a hospital aquarium without a filter therefore ensures that this doesn’t take place.

Setting up the hospital aquarium

Here’s what you’ll need for a hospital aquarium:

  • a container/aquarium, 10L minimum
  • a sponge, bio or sponge/bio filter
  • a heater (what type of heater can depend on the illness)
  • a thermometer

Start by filling the aquarium with FRESH treated water, follow our steps for water treatment on our water treatment page here. Also, some treatments for certain illnesses involve adding aquarium salt to the water. Make sure that you add the correct amount of salt per litre/gallon into the hospital aquarium. Different amounts of salt will be needed depending on the illness so be sure not to overdose/underdose. Remember that, depending on the illness, your fish may not even need salt in the water. Only add salt if it is truly necessary.

Next add the filter, either a sponge or bio or a mixture of both will do. Make sure you DO NOT add a filter with any carbon to the hospital aquarium as the carbon will remove any medication that you introduce to the hospital aquarium.

Small aquarium heaters with an adjustable temperature tend to be expensive but it may be what you need to save your fish. To combat certain illnesses, you’ll need to raise the temperature of the water above standard living temperature. For example, a betta thrives at any temperature between 76℉ and 82℉, but you may need to boost the temperature to above 80℉ or 85℉ to tackle some illnesses.

Alternatively, you may need to lower the temperature. For example, a fungal infection may react differently to a bacterial infection when the temperature is hired/lowered. You can read more about optimal heating here. During treatment, ensure that the hospital aquarium stays at a stable temperature; a fluctuating temperature can stress the fish, which will only worsen the ailment – make sure you have a reliable thermometer and check it regularly.

Once you have the water added, the filter on, and the heater set to the correct temperature,  leave the aquarium to run for 24 hours before adding the betta to it. When the aquarium is ready, add the fish and proceed with the required medication. Instructions for adding the medication should be specified on the packaging of the medication itself. You can also read about medication for specific illnesses on our betta disease and illness pages.