Properly Acclimating Your Tropical Fish

We often use the phrase acclimating your fish when making a purchase at the local pet shop. This is basically the correct term for moving the fish into a new aquarium environment, that may have different water parameters than the source tank at the store. This transfer is to take place with as little or no stress to the fish as possible. No matter which species of fish, or how hardy it’s reported to be, by introducing the fish slowly into the tank and letting them get used to the water over a period of time, we are ensuring that the fish will settle better and not be faced with any sudden changes in water parameters.

One of the biggest concerns is pH shock, as the fish could suddenly go from soft acidic water to hard water, or vice versa. This could seriously affect the health of the fish if allowed to happen. Getting the fish into your tank with the least amount of stress doesn’t start when you get home, it starts when you first purchase the fish from a supplier or breeder. It is more than likely that your supplier or breeder will not have the same water parameters as yourself, and a good tip is to ask, so that you have a good idea how much acclimation will be required to get the fish settled into your tank. If the parameters are similar, then the process will be much easier.

Any supplier that is worth dealing with will always use the same routine when bagging the fish. Care should be taken when netting the fish, as to not to cause excessive stress for the fish. In many cases, especially fish with spines, the fish should be double bagged or even triple bagged so that if the spines tear one bag then the water still cannot escape. There should be at least twice as much air in the bag as water, as the water is not going to leave the bag but the oxygen will be depleted over a period of time. Some suppliers will even pump oxygen into the bag, as well as a squirt of an anti-stress formula. The bag should then be placed in a darker bag to reduce the light, as this will keep the fish more settled until you get it home.

Adding the Fish to the Tank

Turn off any aquarium lighting, this can also shock the fish if they leave a dark place to be placed in an illuminated tank straight away. Open the bags and roll down the edges, this will allow the bag to float without tipping over. Float the bags for at least 20 minutes to allow the temperature of the water in the bag to equal the water in the aquarium. Aquarium water can now be slowly introduced into the bag, about 1/2 cup at a time, every 5 minutes or so. As the bag becomes full, it’s time to release the new fish into the tank. We prefer to net the fish out, rather than tipping the bag into the aquarium. Doing this will prevent any waste or possible contamination entering your tank.

Allow the fish to explore the tank for a couple of hours before switching the lighting back on. Normally we won’t feed the fish straight away, and will let them settle in first. Sometimes a light feeding will keep curious tank mates occupied and away from the newcomers though, so that’s up to you.

In some case it can take days or weeks before the fish are fully acclimated to your tank. Always keep a close eye on any new fish for a couple of weeks to make sure that they are showing no signs of stress or the initial symptoms of any disease. Always make sure that they get their fair share of the food at feeding time, and are not being picked on or intimidated by their tank mates.

If acclimated correctly, your fish will be healthier and have long and happy lives.

Steven Sannan is currently a member of the staff, with 35+ years of fishkeeping experience. Experience that includes extensive freshwater, saltwater and pond keeping knowledge.

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