Nothing beats the excitement of spotting the perfect addition to your aquarium, whether it’s a vibrant shoal of Tetras or a stunning marine Angelfish. However, the journey from our tanks in Westerleigh to your home is a big event for a fish, and how you handle the first hour makes all the difference to their long-term health.
At South West Tropical & Marine, we want your new livestock to thrive. Here is our guide to settling your new tank mates in safely.
Why is Acclimatisation Important?
Water parameters (pH, temperature, and salinity) vary from tank to tank. Even if your water quality is perfect, it will be slightly different from the water in our shop. Moving a fish too quickly causes “osmotic shock,” which can damage their immune system. Patience is key!
Step 1: Dim the Lights
Fish are sensitive to light, especially when they are stressed from a car journey. Before you start, turn off your aquarium lights. This lowers the stress levels in the tank and prevents existing residents from getting too aggressive with the newcomers.
Step 2: Float the Bag (Temperature Match)
Place the sealed bag containing your new fish gently onto the surface of your aquarium water. Let it float there for about 15 to 20 minutes.
- Why? This allows the water inside the bag to slowly adjust to the same temperature as your tank, preventing thermal shock.
Step 3: The Mixing Phase (Chemistry Match)
Once the temperature is matched, open the bag and roll down the top edges to create a floating ring (or use a peg to secure it to the side).
- Over the next 20–30 minutes, slowly add a small amount of your tank water into the bag (about half a cup every 5 minutes).
- Why? This gradually introduces the fish to your specific pH and water chemistry.
Step 4: Net and Release
Top Tip: Never pour the water from the bag into your tank! The bag water contains waste produced during the journey. Instead, gently use a soft net to transfer the fish from the bag into your aquarium, then discard the bag water down the sink.
Need Advice?
Every tank is unique. If you are buying sensitive species like shrimp or specific marine invertebrates, the acclimatisation process might need to be slower (such as drip acclimation).
If you are unsure, just ask a member of our team when you visit us in Westerleigh. We are always happy to share our advice to ensure your South Gloucestershire aquarium remains a healthy, colourful underwater world.