How Many Corals Can You Add At One Time?
We often get asked by both novice and experienced reef keepers how many corals can you add simultaneously to your aquarium. While the enthusiasm to create a vibrant underwater landscape is understandable, there are various factors to consider to ensure the long-term success of your aquarium reef system.
The Fundamentals of Coral Addition
The process of adding corals to your aquarium isn’t merely about how much space is available or aesthetic arrangements - it is a delicate balance that involves understanding your aquarium system’s carrying capacity, biological filtration capabilities, and the complex coral interactions among different species.
So, the number of corals that you can safely add at once depends on your aquarium’s stability and maturity.
Tank Maturity & Its Importance
A mature reef tank is one that has been successfully running for a minimum of 6 months, has developed the biological filtration needed, and bacterial populations are under control. A ready system will also have:
- Stable water chemistry/parameters
- A robust population of beneficial bacteria
- A well-established nutrient cycling process
However, we should note that adding too many corals at once can disrupt this delicate ecosystem even in mature aquarium systems.
What to Consider When Adding Corals to an Aquarium?
Tank Size & Bioload
The volume inside your aquarium plays a key role in determining how many corals you can add at once. For example, larger aquariums typically offer more stability and can deal with more additions. However, always consider your current bioload.
Bioload includes:
- Your fish population
- Invertebrate population
- The current nutrient levels
- The number and size of existing corals inside your aquarium
At Reefco Aquariums, we suggest not increasing your total coral mass by more than 20% at any given time, regardless of how big or small your tank is. This way your corals will be less stressed and they will thrive more.
Water Quality
When you add new corals to your aquarium, it creates additional bioload on your system’s filtration capacity. This is because each new coral introduces potential hitchhikers, new nutrient demands, organic matter, and added waste production.
Your aquarium’s system needs time to adjust to these changes, and therefore, your filtration must be able to handle the increased load.
Coral Types
Different coral types/species have varied demands on your aquarium system, which affects how many corals you can add at once.
Soft corals like zoas, mushrooms, and leather corals, typically create less stress on a system when added to an aquarium. They are also more forgiving of parameter fluctuations and produce less aggressive chemical compounds than their coral cousins. For soft corals, we recommend adding only 3-4 small colonies of soft corals to a mature 100-gallon aquarium at once.
On the other hand, LPS corals require more careful consideration. LPS corals tend to have higher calcium and alkalinity demands and can be more sensitive to water parameter changes. When adding LPS corals to an aquarium, we advise limiting to 2-3 corals at one time in a 75-125 gallon aquarium.
Now for the most needy corals of them all - SPS corals. These corals are the most demanding in the hobby, plus they are much more sensitive to parameter fluctuations. SPS corals require the most stable conditions and have the highest demands when it comes to calcium and alkalinity. Therefore, we suggest adding only 1 or 2 SPS frags at one time, even if you have a larger reef aquarium, and monitoring the water parameters closely.
A Conservative Approach to Adding Corals
The majority of reef keepers opt for a conservative approach, and we back this as it is the best for long-term results.
Always start with a small number of hardy corals and observe your aquarium system over a few weeks before adding any more. During the observation period, monitor parameter stability, identify any potential issues early, observe coral behavior, and adjust your care routines accordingly.
While it is not always done (naughty hobbyists), quarantining new corals can greatly reduce the risk of introducing aquarium pests or common aquarium diseases to your aquarium. However, maintaining multiple quarantine tanks may limit how many corals you can add to your system at one time, based on your quarantine space.
Special Considerations for Adding Corals
- Seasonal timing: Believe it or not, the time of year can affect how many corals you should add at once. For example, during the warmer months, shipping stress is increased, while in the winter months, heating costs and tank stability may be a concern. During these stressful periods, you may want to reduce the number of how many corals you add at one time.
- Aquarium system age: Although we have mentioned this earlier, we want to emphasize that newer systems are less stable for adding corals. If your aquarium system is less than six months old, we advise adding only 1 or 2 coral frags every few weeks.
Essential Water Parameters to Check
- Alkalinity
- Calcium
- Magnesium
- Nitrate
- Phosphate
- Temperature
We recommend testing these parameters daily for the first week after adding any new corals into your aquarium, then every couple of days in the following weeks.
Summary
The number of corals that you can add to your aquarium at one time isn’t a fixed number, but rather a careful consideration of different factors. While you may be tempted to quickly populate your reef aquarium, taking a careful and measured approach will lead to better and longer success.
Remember that to be a successful reef hobbyist, it is often about patience and observation rather than rushing into creating your dream aquarium. If you would like to learn more about adding corals to your aquarium or would like advice on coral compatibility, contact the Reefco Team today! Happy reefing!
