How to add new fish to your aquarium
Taking home a new fish is exciting - but now you have to begin the delicate process of introducing it to your aquarium.
It’s vital to let a new fish acclimate in a new environment. Dropping it straight into the water can cause pH shock, ‘new tank syndrome’, or just an unnecessary amount of stress; all of which can kill your new pet.
Thankfully, that’s easily avoided with the right method. Here’s what Oase recommends.
Preparing to add a new fish
Before introducing the new fish, there are a few things you can do to keep your aquarium in good condition, help the new additions adjust, and make the change easy on your current inhabitants.
Test the water. Check the pH levels and make sure ammonia and chlorine levels both read zero.
Turn the aquarium light off. The light itself can cause distress. Don’t switch it back on for a few hours – or preferably a couple of days.
Add a little food. Doing so right before you add the new fish will keep your current inhabitants distracted and satisfied – which can also help prevent any territorial behavior.
Expert tip
Move a few decorations around the aquarium a day or so before you introduce the new fish. This distracts your existing fish and makes them more interested in their surroundings than in the new additions. It means all your fish can explore a new environment at the same time.
Should I quarantine my new fish before adding it to the tank?
Ideally, yes – new fish should be quarantined in a separate tank for two weeks before adding them to your main aquarium. This helps you spot any issues, such as disease or infection, in the new fish before they can affect your aquarium.
Of course, that isn’t always an option, especially if you’re new to fish-keeping. If you need to add new fish straight to your aquarium without quarantine time, just remember to keep an eye on them over the next few weeks.
How to add a fish to your aquarium
The most common way to add new fish to an aquarium is using the floating method, introducing it gradually to the water using a bag.
Put the fish in a clean, transparent plastic bag. If it came in a bag when you bought it, you can keep it in that one. Make sure the bag is closed.
Float the bag in the aquarium. Keep it there for around 10-20 minutes, so the water in the bag can acclimatize to the tank’s temperature. Be sure to monitor your new fish during this time to check it’s doing okay.
Open the top of the bag and roll down the sides to create an air bubble so it can float.
Add a little water from the tank into the bag. Wait a few minutes (not more than 10 minutes), then add some more. This part of the process may take up to about an hour overall.
Add the fish to the tank. Use a small net to lift it out of the bag and place it in the water. Finally, remove the bag and discard the water inside it.
What behavior to expect from a fish in a new tank
When fish are first introduced to a new environment, such as your aquarium, they tend to be a little stressed at first. Expect them to hide amongst the plants and decorations, or to swim erratically. They’re also likely to expel a lot of waste at first.
This is all normal behavior – rest assured they’ll calm down once they get acquainted with the tank.
After a couple of days, the new fish will start exploring the tank. They’ll be hiding less and swimming more and starting to behave like the rest of your fish.
How to help a new fish de-stress
Keep the aquarium lights off for a few days
Make sure they have lots of cover and hiding places – think plants, rocks, and other sheltering areas
Don’t move or change anything in the tank for a couple of weeks
Feed them sparingly at first
Monitor the water chemistry, especially the ammonia and nitrite levels, as the waste the new fish produces can affect these
FAQ
How long do fish stay in the bag before I add them to the tank?
About 60-90 minutes overall. First, float the bag closed for about 10-20 minutes. Then open it and start adding in aquarium water – a little every few minutes for an hour or so.
How do I transfer a new fish from the bag to the tank?
A small fish net is the best way. Just use the net to lift the fish out of the bag and into the tank. Avoid tipping the contents of the bag straight into the tank.
How do I introduce a new fish to my other fish?
The floating method, using a bag, is a tried and tested way of introducing new fish to an aquarium in a way that doesn’t disturb the existing fish. There are a few things you can do to keep your current fish occupied and stop them from getting territorial – such as adding a bit of food to the tank and rearranging the decor beforehand.
How do I quarantine a new fish?
You’ll need a separate tank to quarantine a fish. Add your new fish to the separate tank using the floating (or bag) method outlined above, then wait two weeks, keeping an eye on the fish’s health and how it’s behaving. If it seems happy and healthy, you can transfer it to your main aquarium, again using the bag method.
How long should I keep the lights off when adding a new fish?
You should keep the aquarium lights off for an absolute minimum of 1-4 hours. But it’s generally recommended to keep them switched off for one or two days.
How soon can I add fish to a new tank?
Wait until your new aquarium has completed its first cycle and you’re happy with the