Acclimating New Fish

Acclimating New Fish

A Step-by-Step Guide to Acclimatising New Fish to Your Aquarium

Bringing new fish home is an exciting time for any aquarium enthusiast. However, the transition from the shop to their new home can be a stressful experience for your new aquatic friends. To ensure their survival and long-term health, it is crucial to acclimatise them properly. This process allows the fish to adjust to the temperature and water parameters of your aquarium, minimising shock and stress. This guide will walk you through the correct way to introduce new fish to their new environment.

Why is Acclimatisation So Important?

Fish are sensitive creatures and sudden changes in their environment can be detrimental. The water in the transport bag will have different temperature, pH, and nutrient levels compared to your aquarium. Acclimatisation is the gradual process of equalising these parameters, allowing the fish’s body to adjust without being overwhelmed. Skipping this crucial step can lead to stress, disease, and even death.

Preparing for Acclimatisation

Before you begin, make sure you have the following ready:

  • A bucket (for the drip method)
  • Airline tubing (for the drip method)
  • A clip or valve to control water flow (for the drip method)
  • A net
  • Scissors

It is also a good idea to dim the aquarium lights to create a calmer environment for the new arrivals.

Method 1: The Floating Bag Method

This is the most common and straightforward method for acclimatising most freshwater fish.

Step 1: Float the Bag

Turn off the aquarium lights and float the sealed bag in your aquarium for 15-20 minutes. This allows the water temperature inside the bag to slowly match the temperature of your aquarium water.

A bag with a fish inside floating in an aquarium to acclimatise.
Float the bag to equalise the water temperature.

Step 2: Add Aquarium Water

After 15-20 minutes, open the bag and roll down the top edges to create a floating ring. This will keep the bag upright. Add about a quarter of a cup of your aquarium water to the bag.

Step 3: Repeat

Repeat the process of adding a quarter of a cup of aquarium water to the bag every 5-10 minutes for the next 30-60 minutes. This will slowly adjust the fish to the pH and other water parameters of your tank.

Step 4: Release Your Fish

Once the bag is mostly full of aquarium water, you can gently net your fish out of the bag and release them into the aquarium. It is important not to add the water from the bag into your aquarium, as it may contain waste products or diseases from the shop’s water.

Method 2: The Drip Acclimatisation Method

The drip method is a more gradual and gentle way to acclimatise fish, and is highly recommended for more sensitive species, such as discus, wild-caught fish, and most marine fish and invertebrates.

Step 1: Prepare the Bucket

Place your new fish and the water from the transport bag into a clean bucket. Ensure there is enough water to keep the fish submerged. Place the bucket on the floor next to your aquarium.

Step 2: Start the Siphon

Using a length of airline tubing, start a siphon from your aquarium to the bucket. You can do this by submerging one end of the tube in your aquarium and sucking on the other end until water starts to flow. To control the flow rate, you can tie a loose knot in the tubing or use a flow control valve. You are aiming for a drip rate of 2-4 drips per second.

Step 3: Let it Drip

Allow the water to drip into the bucket until the volume of water in the bucket has at least doubled. This can take anywhere from 30 minutes to an hour. This very slow and gradual introduction of the new water parameters is much less stressful for sensitive fish.

Step 4: Release Your Fish

Once the water volume has doubled, you can gently net your fish from the bucket and release them into the aquarium. As with the floating bag method, discard the water in the bucket and do not add it to your tank.

After Acclimatisation

Once your new fish are in the aquarium, keep the lights off for a few more hours to allow them to settle in. It is normal for new fish to hide for a while. Avoid feeding them on the first day, as they may be too stressed to eat. Keep a close eye on your new additions for the next few days to ensure they are settling in well and are not being bullied by other tank mates.

By following these simple steps, you can ensure a smooth and stress-free transition for your new fish, setting them up for a long and healthy life in their new home.