Cycling your first aquarium can be really exciting, but also create a bit of anxiety. You got your hand's wet building and setting up the tank, filled it with water, and then asked to wait for 4 weeks or more before you even looking at a fish. When the day finally comes, those nitrates start to show up and you are preparing to get your first animals in the tank, its important to take the right steps for a smooth transition from a cycling tank to a functioning aquarium. We boiled it down into 8 easy steps that you should take after your saltwater aquarium has cycled. 

Before we dive in, be confident your not acting prematurely.  It is important to give your tank plenty of time to establish the nitrogen cycle and when in doubt, just wait longer.  It is better to be patient with just about everything related to keeping an aquarium, nothing good happens fast. In a nutshell, nitrates will be detectable using your nitrate water test kit and ammonia and nitrite should be zero. You can always just give yourself a refresher course by checking out Episode #18 of the Beginner's Guide for a quick review of the nitrogen cycle and how to know when your cycle is complete.

1. Clean Up

You want to clean up things inside the tank before performing your first water change.  Start by scraping any algae or bacteria growth from the glass walls and/or equipment inside the tank. Using a bulb syringe or small water pump, gently blast the rockwork or decoration to rinse out detritus that may be collecting or trapped in the crevices. Any remove debris or algae will then float suspended in the water and can be filtered out via your mechanical filtration. Be sure you have installed a fresh filter sock or replaced your filter pads/sponges so removal of that debris is effective.

2. Water Change

Immediately after you finish cleaning, you can perform a larger water change. Somewhere in the range of 20% - 50% of the total water volume and we typically recommend you lean on the larger end of that spectrum. This will not only help remove some of that suspended debris, but it will also dilute or remove a portion of those nitrates you created during the cycle. Freshly mixed seawater, whether you bought it from the store or mixed it yourself, will contain balanced levels of all the major, minor, and trace elements to which helps to replenish those levels in your tank.

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3. Add Livestock

Finally! Your patients will be rewarded but please resist the temptation to stock the tank too fast or purchase fish you are not prepared to care for properly. Stocking your tank will be a process and you will always need to research the animals before you buy them and never add too many animals at one time.  A good general rule for most tanks under 100 gallons, never add more than 2-3 fish at one time and no less than 2 weeks in between new additions.

This gives the beneficial bacteria foundation time to "cycle" based upon the new addition of nutrients (fish food and poo). Every time you add new fish, the bacteria that support the nitrogen cycle in your tank will adjust their populations to accommodate that newly available bioload. More fish = bigger bioload = more bacteria and that bacteria just needs a little time to grow.  

Bioload = The amount of waste in your tank including fish waste, leftover food, and decomposing organic matter. 

If you have not done so already, go set up a quarantine tank which should be the protocol for all your new fish and in many cases corals too! QT tanks are easy to set up and do not require much effort so if you want to ensure the long-term success of your tank, you will be the proud owner of a QT tank. 

There are options for purchasing pre-quarantined fish as well. This means your local fish store or retailer isolates, observes, and medicates (if necessary) for at least 30 - 90 days before selling you the fish. This ensures the fish will not bring diseases or parasites into your aquarium and prepares the animals for life inside a tank. This would really be the only scenario in which you should introduce a fish directly into your display without going through a period of quarantine first. 

How many fish can I have?

There is no hard-fast rule for this but it is always better to be conservative. A bigger tank means you can have a bigger bioload. Some fish are big and some are small. So, while we cannot give you an exact number per gallon, follow the rule of never adding too many at one time. Your very first fish should be hardy species like clownfish or any one of the more peaceful damselfish species.

If we take the most common tank size into consideration here, tanks ranging in size from 10 - 30 gallons can safely house 2 - 4 fish during those first few months.  

Test your waste levels often.

When adding fish, you want to monitor both ammonia and nitrite closely.  Should you start to see ammonia and nitrite show up, that means your bacteria are not keeping up with the bioload and a large water change should be performed. This will remove that toxic ammonia and/or nitrite keeping it safe for your fish inside.  

A healthy or well-adjusted aquarium will show undetectable levels of ammonia and nitrite while nitrates begin to start stacking up slowly as you add fish and begin to feed them.

When do I get corals?

If this is your first time, it is is simply best to wait and not add any corals right away. You want to wrap your head around the required husbandry it takes to maintain stable water parameters before attempting to add coral. It just makes sense and will reduce the risk of becoming frustrated.  

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#4. Turn On The Lights

Most of the time, it is best to keep your lighting turned off during the cycle as it will reduce the growth of photosynthetic organisms such as algae. Once you add fish, it is safe to go ahead and program your lights to run a day/night helping imitate the natural environment for your fish.  This also illuminates the fish themselves helping you appreciate their natural beauty.  

Yes, nuisance algae are going to begin to grow much faster which is 100% normal. You will find yourself cleaning your glass more often and start to become curious about "cleanup crews". Clean-up crews are an army of invertebrates and utilitarian fish designed to help consume both nuisance algae and detritus in your tank.  For now, just keep the glass clean and don't let your nitrate levels stack up severely, and just wait until step #6. 

#5 Prepare Yourself For Diatoms

Along with nuisance algae, you're going to notice some light brown dust start to grow on the surfaces in your tank which are diatoms. Diatoms' bark is way bigger than their bite. While they look terrible, they are normal and all tanks go through a diatom bloom.  There may also be other organisms that show up to such as cyanobacteria and dinoflagellates.  Many hobbyists have dubbed this "the ugly stage". The populations of these organisms may rise and fall multiple times.

It is best to go through the effort of cleaning this stuff out of the tank which requires effort and increased maintenance. You should have a water change schedule and be cleaning your sand bed as well as blowing off the rocks and cleaning the glass walls on a regular basis.  The idea is to stay a step ahead and don't let it get really bad. For example, using your magnetic algae scraper daily is much easier than waiting to do it weekly as it only allows thicker layers of algae to form which are more difficult to remove. 

Adding nutrients to the tank by adding fish and turning on your lights sparks this stage. It happens in all tanks, sometimes is more severe than others and some tanks seem to just get lucky and skip the ugly stage altogether.  In time, tanks will stabilize and these outbreaks become less severe and far less common if they happen at all.  This is all thanks to those beneficial bacteria we talk so much about, as time progresses the bacteria become more robust and diverse which starves out competing organisms such as algae and various other ugly, pesky organisms. 

#6 Add A Clean Up Crew

Clean-up crews are utilitarian fish and invertebrates that can help consume algae and detritus, helping reduce that ugly stage. Most tanks will get a variety of snails and crabs that burrow in the sand consuming waste (detritivores) or crawl around the rocks and glass walls mowing down algae (algae eaters). To learn more, check out this episode from our popular 52 Weeks of Reefing video series where Ryan explores clean-up crews and lists some of our favorite options.

#7 Learn To Be Patient

Learning to maintain a successful saltwater aquarium takes practice. You have got to keep a good attitude and take every failure as a learning lesson. ALL aquarists will go through some hard times. Nasty algae outbreaks, sick fish, the dreaded dinoflagellates...stuff happens, and just don't give up. The key here is to learn from it because these are the things that make you a successful and skilled aquarium owner.  Understanding why these things happen, overcoming them, and preventing them from coming back. 

A considerable percentage of hobbyists quit during the first year because they experience failure of some kind. They say it takes 10,000 hours to master new skills, so don't fault yourself for making some mistakes the first time around. The only way you are going to fail as a hobbyist is to quit and break down the tank.

#8 Establish A Maintenance And Testing Regiment

The best thing you can do to avoid some of those failures we just talked about is to make a commitment to your tank. Establish healthy husbandry habits now, your tank will reward you.  You're going to need to perform water changes every 1-2 weeks, you will need to test the water weekly and of course, feed the fish and clean the glass daily. Build this routine into your schedule and budget for the necessary time needed to perform the maintenance. If you can fall into a rhythm it won't be so tedious which means you're far less likely to neglect it. 

You should be monitoring temperature, pH, salinity, and nitrate levels closely during your first few months. It is a great idea to keep a log of your test results and take notes when you add new fish or make changes to the tank. This way you can go back and reference things down the road.  Should you decide to keep corals, monitoring water chemistry is only going to become more critical so take the time to hone the skills now.