Is Your Fish Sick? Don’t Wait – Quarantine It
Learn how to quarantine a sick fish the right way. Easy setup, medicine tips, and daily care to help your fish recover fast and protect your tank.
Table of Contents
- Why Quarantine Is Important
- How to Set Up a Quarantine Tank
- How to Give Medicine Safely
- Oxygen and Clean Water Are Very Important
- Stay Calm: Your Energy Affects Your Fish
- Faq
- Conclusion
When you notice that your fish isn’t swimming normally, has white spots, clamped fins, or just seems unwell, it’s important to take action right away. One of the best things you can do is move the sick fish into a separate tank—this is called a quarantine tank. A quarantine tank gives your fish a clean, calm space to rest and recover without stress from other fish. It also protects your healthy fish from catching the same illness. In this blog, we’ll guide you step-by-step on how to set up a quarantine tank, give medicine the right way, and care for your fish during recovery—all in a simple and beginner-friendly way.

Why Quarantine Is Important
Quarantining a sick fish is very important. It helps in two major ways:
First, it prevents the disease from spreading to your other healthy fish in the main tank. Fish illnesses can spread quickly in shared water, so moving the sick one out protects the rest of your aquarium.
Second, it gives your fish a peaceful place to heal. In the main tank, other fish may bother the sick one, and water conditions may not be ideal for treatment. In a small, quiet tank, your fish can relax, and you can treat it properly without worrying about harming anything else. Important Note: Never use medicine directly in your main tank! It can harm your plants, helpful bacteria, and even healthy fish.
How to Set Up a Quarantine Tank
Setting up a quarantine tank is easy. You don’t need anything fancy, just the basics. Here’s how to do it the right way:
• Use 100% water from your main tank: This helps avoid stress because the fish is already used to this water.
• Don’t add gravel, plants, or decorations: A bare tank is easier to clean and lets you see waste or leftover food.

• Add a sponge filter or air stone: This keeps oxygen flowing and the water gently moving.

• Use a heater to keep the temperature stable: Sick fish don’t handle temperature changes well.

How to Give Medicine Safely
Giving medicine can help—but it must be done correctly. Here's how to do it the safe way:
- Figure out what kind of illness your fish has (white spots, fungus, swollen belly, etc.).

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Buy the right medicine for that illness. Ask your local pet store or check trusted aquarium websites.
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Read the label carefully and follow the instructions. Don’t guess the amount!
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Mix the medicine well in the quarantine tank water.
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Watch your fish after adding medicine. Make sure it's not acting worse or more stressed.
Be careful: Using too much medicine (overdosing) can harm or even kill the fish. Always measure correctly!
Oxygen and Clean Water Are Very Important
When a fish is sick, it needs clean water and lots of oxygen to feel better. Here’s how to make sure your fish gets both:
• Always use an air pump or sponge filter to keep oxygen levels high.

• Change 20–30% of the water every day to keep it clean.

• Remove uneaten food quickly so it doesn’t rot and dirty the water.

• Watch for stress signs, like:
o Gasping at the top of the water
o Hiding all the time
o Losing color or looking pale
These signs mean the fish might be uncomfortable and you need to check the water or oxygen levels.
Stay Calm: Your Energy Affects Your Fish
It’s natural to feel worried when your fish is sick—but remember, fish can sense stress in their environment. Sudden movements, tapping on the glass, or constant checking can make things worse.
Here are a few tips to help you and your fish stay calm:
• Stay relaxed when observing your fish
• Don’t change or mix treatments too often
• Be patient—healing takes time
• Avoid loud noises and sudden movements near the tank
Remember: Relax and nurture your passion. Excessive excitement or treatments could harm your unwell fish. A calm environment helps your fish heal better.
Faq
1: What is a quarantine tank?
A quarantine tank is a small, separate tank used to keep sick or new fish away from your main aquarium.
2: Why can’t I treat the sick fish in the main tank?
Medicine can harm healthy fish, plants, and good bacteria in your main tank.
3: How long should I keep a fish in quarantine?
Usually 7 to 14 days, or until the fish is fully recovered.
4: Can I use tap water in the quarantine tank?
Only if it’s treated with dechlorinator. It’s best to use water from your main tank.
5: What if I don’t have a sponge filter?
Use an air stone with an air pump—it will help provide oxygen.
6: How do I know if my fish is getting better?
You’ll see it swimming normally, eating well, and its color will look brighter.
7: My fish is still not eating. What should I do?
Check water quality, reduce stress, and continue treatment. Give it time.
8: Can I quarantine more than one fish together?
Yes, if they have the same illness and are not aggressive toward each other.
9: Do I need a big tank for quarantine?
No, a small tank (10–20 liters) is usually enough for one or two fish.
10: When should I start quarantine?
As soon as you notice any signs of illness—don’t wait!
Conclusion
Taking care of a sick fish doesn’t have to be scary. With a simple quarantine tank, clean water, and the right medicine, you can help your fish recover faster and keep your other fish safe. Always act early when you see something wrong—it’s the best way to give your fish a chance to heal.