Everything You Need to Know About Quarantining Marine Fish

Quarantining your new fish might sound like extra work, but it’s one of the best ways to ensure your tank stays healthy. Imagine all the hassles you could avoid with a little extra patience upfront. In this guide, we’re diving deep into why quarantining is crucial, how to do it properly, and how it can save your marine ecosystem in the long run.

Why Quarantining Your New Fish is a Must

When you add new fish to your tank, you’re not just introducing a creature to your water – you’re introducing potential diseases, parasites, and pests. Even if the fish looks healthy, it can still carry hidden problems that can quickly spread to the rest of your aquarium. This is where quarantining comes in. It gives you the time and space to observe your new fish, making sure it’s healthy before it mixes with the rest of your aquatic community. It’s the ultimate health insurance for your tank.

The Benefits of Quarantining Marine Fish

1. Prevention of Disease
One of the biggest benefits of quarantining is preventing the spread of diseases. Marine fish can carry illnesses like white spot or velvet disease that may not show symptoms immediately. By isolating them, you can spot early signs of infection and treat them before they spread.

2. Parasite Control
Marine fish are often exposed to parasites in their natural environments. These microscopic invaders can hitch a ride on your new fish and spread to your other tank inhabitants. Quarantining ensures that parasites like ich or flukes don’t make their way into your main tank, keeping your aquatic ecosystem thriving.

3. Acclimatisation
New fish need time to adjust to their new environment. By quarantining them, you can gradually acclimate them to the temperature, water conditions, and other parameters in your display tank. This helps reduce stress and encourages better health, improving your fish’s chances of thriving in the long run while protecting your existing inhabitants.

4. Reduced Stress on Your Main Tank
Introducing a new fish directly into your main tank can upset the delicate balance you’ve worked so hard to maintain. By keeping new arrivals in quarantine, you reduce the risk of disrupting the harmony of your established ecosystem. This gives your existing fish time to adjust to the newcomer without added stress.

Setting Up a Quarantine Tank: What You Need

Creating a quarantine tank doesn’t need to be complicated. You don’t need to invest in a fancy setup – a basic tank or any container will do the trick. Here’s what you need to get started:

1. Tank Size
Your quarantine tank doesn’t need to be large – something between 20-40 litres will be sufficient for most marine fish. The size should be enough to allow the fish to swim comfortably, but small enough to make monitoring and treatment easier.

2. Filter
A simple filter will help keep the water clean, but you don’t need anything too elaborate. Make sure the filter is able to maintain water quality, as dirty water can stress your fish, negating the benefits of quarantining. Please ensure you use beneficial bacteria to cycle the system first or you could use old filter media from your existing pest free system.

3. Heater
Marine fish are sensitive to temperature changes, so a reliable heater is essential to maintain a stable environment in your quarantine tank. Ensure that the water temperature is consistent and matches your fish’s natural habitat.

4. Lighting
You don’t need strong lighting in your quarantine tank – the idea is to keep things simple. Dim lighting is fine, as the goal here is to observe the fish without stressing it out.

5. Water Parameters
Test the water regularly for salinity, pH, ammonia, nitrite, and nitrate levels to ensure that your quarantine tank mimics the conditions of your main tank as closely as possible. This will help the fish adjust smoothly when it’s time for them to move.

Quarantine Duration: How Long Should You Isolate Your Fish?

The recommended quarantine period is usually 2-4 weeks. This gives you enough time to observe your new fish for any signs of illness or parasites. The first 10-14 days are the most critical. During this time, watch for any unusual behaviours such as scratching against rocks, rapid breathing, cloudy eyes, spots, or lack of appetite.

If you notice any symptoms, it’s important to treat them promptly. By catching issues early, you can prevent them from spreading to your main tank.

What to Look For During Quarantine

You should always keep an eye out for signs of disease during the quarantine period. These include:

• Visible spots or lesions: White spots on the body or fins often indicate ich, while velvet disease presents as a dusty, goldish appearance on the fish’s body.
• Erratic swimming: Fish that are swimming erratically or scratching against objects may have a parasite problem.
• Loss of appetite: A lack of eating can indicate stress or illness, which should be addressed right away.
• Breathing issues: Rapid gill movement or laboured breathing can be signs of stress or infection.

If you spot anything unusual, act quickly. Quarantining gives you the best chance to catch problems early, before they spread to your main tank.

How to Treat Fish in Quarantine

If you notice signs of illness or parasites, there are a few treatments you can try in your quarantine tank. Depending on the issue, you might use medications like copper-based treatments for parasites, praziquantel for flukes and worms, methylene blue for fungus or formalin for external parasites. Always read the instructions carefully and follow the recommended dosage. Voogle or Dr Tim’s First defence are greats additions to help naturally boost your fishes immune system during this period.

There are only 3 recognised methods that will remove unwanted parasites from your fish.

1) Copper

Copper is and always will be our go to for treating the disease, but not all fish can handle copper treatments. Be wary of scaleless fish and angel's as they do no like heavy treatments of copper. For these guys you will need to add the copper in to your quarantine system slower over the course of a few days to get them acclimated to it or use one of the other treatments below. Copper will also kill inverts and corals, they can not get infected by Cryptocaryon Irritans but can be harboured into your system by the water they are transported in.

Treating New Fish

In a quarantine tank you will need to treat your new fish for a minimum of 2 weeks while maintaining your copper levels at 0.15 mg/l to 0.3 mg/l, use a good quality copper test kit. In the tank you will want plenty of oxygen in the form of an airpump with airstone/sponge filter, heater, some form of existing media for nitrification and some hiding spaces (PVC pipes work well). You will want to keep these guys in a low stress, quiet environment. No light is required during this time. They will do well with a variety in their diet of frozen and dry food soaked with a fish food enhancer/vitamin. Dry and frozen food can sometimes lack essential omega 3 fatty acids and other nutrients lost in manufacturing/freezing/storage which is why these enhancers and vitamins are an essential part to add into your fishes diet. Once you have treatment it is advisable to clean out your tank for any traces of copper that may still be in the system by using a treatment or carbon.

Treating fish from your display tank

Treating fish as above will be fine if you run a Fish Only With Live Rock (FOWLR) system. But if you have corals and inverts (or plan to later) you will want to treat in a separate hospital/quarantine tank as copper will soak into live rock, media sand etc. and will leach out over time. For tanks with corals and inverts already you will want to catch all fish out of the tank and treat as above. You will also need to keep your main Display Tank (DT) fishless for minimum of 10 weeks, this will ensure any left over white spots will have finished its life cycle and have died off by not finding a fish as a host. You will want to quarantine all new additions(corals and inverts included) to your tank to ensure you never have the issue again.

Products we have used with success:

1) Fritz Coppersafe

Fritz Coppersafe is a long-lasting, chelated copper treatment designed to effectively combat external parasites like ich, velvet, and other freshwater and marine fish diseases. Unlike some copper-based treatments, it remains active in the water for up to a month, providing continuous protection without frequent dosing. Safe for most fish when used as directed, Fritz Coppersafe does not cloud water and is an excellent option for both home aquariums and quarantine tanks. Always monitor copper levels to ensure the safety of sensitive species.

2) Hyposalinty

This is the process in which we will lower our specific gravity in our water to sg 1.008-1.009 and hold it there for a minimum of 4 weeks from when the last spot has been seen on a fish. This will not work for tanks with corals and inverts. You will also need to monitor PH during this time as there will not be enough salt and trace elements to maintain stable PH. Do not raise or lower you sg by more than 1.002 a day, as salinty shock can stress and kill the fish.

3) Tank Transfer Method (TTM)

This is the process in which we will need two separate holding tanks. You will need air pumps, air stone/sponge filter and an ammonia binder. You will start by putting the fish in to hospital tank 1, leave the fish in there for a MAXIMUM of 72 hours. When the transfer is to happen, you will need to ensure that hospital tank 2 has matching PH and SG. Take fish from tank 1 and transfer to tank 2. There is an option here to have an extra bucket of water to give the fish a quick fresh water dip to avoid contamination, also use different nets for each tank. After this, you will need to ensure that tank 1 is thoroughly cleaned and disinfected with bleach or vinegar and completely dried of any contaminants ready for another round of transfer. You will need to repeat this process a minimum of 4 times, with each time not exceeding 72 hours. This will ensure that white spot does not have enough time to properly attach to a fish and reproduce.

It’s also a good idea to isolate the affected fish for further observation if you detect symptoms. Quarantining allows you to treat and monitor the fish without risking the health of your other tank inhabitants.

After Quarantine: How to Move Your Fish to the Main Tank

Once your fish has been in quarantine for the recommended period and you’re confident it’s healthy, it’s time to introduce it to your main tank. Slowly acclimate the fish to the water conditions of the main tank by floating the bag with the fish in the aquarium for 15-20 minutes. This helps the fish adjust to temperature differences.

Once acclimated, you can gently release the fish into your main tank. Keep a close eye on it for the first few days to make sure it settles in smoothly and doesn’t show signs of stress or illness.

Bottom Line

Quarantining your marine fish is one way to ensure your aquarium is healthy. Adequate monitoring and treatment of newly arrived fish is done to curb the risks of spreading diseases and parasites. The positive aspects far eclipse the effort required to quarantine fishes in a particular tank. By setting aside time to quarantine your fish, you are taking the right step to have a healthy and beautiful aquarium for the next couple of years.

Contact Us Today at Hurstville Aquarium!

Are you looking to purchase new marine fish for your aquarium? We at Hurstville Aquarium are willing to help you with all your aquatic needs. We are committed to delivering you the happiest, healthiest fish for you.