The aquarium hobby is addictive—there is just no way around it.

If you are anything like me, your enthusiasm and passion for aquarium keeping goes through highs and lows. Often accompanying these highs and lows is the desire to change aquariums. Most of us fantasize about upsizing to a larger system. Of course, life sometimes dictates the need to downsize to a smaller tank.

Moving into a bigger/smaller aquarium can be a challenge, so I thought I would share my experiences changing tanks over the years to help you go big or go nano.

The Three P's: Plan, Purchase and Patience

  • Plan ahead
    Decide what size aquarium you want to go with, make sure the dimensions of the tank fit the area you would like to place it and research the equipment required for the new setup. If possible, come up with a "wish list" of items you need to get the tank up and running (the "Save for Later" option in the Shopping Cart is a great way to do this). If you have questions about what you may need or would like a second opinion, we are always here to help.
  • Purchase the items for your aquarium
    Whether you are able to purchase them all at once or need to slowly piece the tank together over time, make sure you buy all the necessary items before attempting to set up the tank. By having all the items on hand, you can make sure everything fits without any issues when the time comes build the tank. Once everything has been purchased, I recommend setting up the tank for a "dry run" without any water. That way, you can cut and glue plumbing return and drain lines and allow ample time for them to dry. This will also give you an opportunity to visualize where everything will be located (heater/chillerprotein skimmercalcium reactor, etc.) to make sure there are no complications or missing items.
  • Patience
    This is the hardest part of the hobby. Most of us want a thriving tank in our home as quickly as possible. But be patient. From start-up to adding that last fish or coral, having patience and monitoring your aquarium along the way is what will lead to the thriving tank you've been dreaming about. Go slowly and you will be successful.

Handy extras to have around
In addition to the supplies needed for the actual tank set up, there are a few "extra" items that are handy to have around. Some of these items include buckets or other containers to hold fresh and saltwater, towels (lots of them to wipe up accidental spills), tarps (to protect your floor from spills), water pumps and tubing (if you need to pump premixed saltwater into the new tank).

If you have a deep sand bed, you need to be careful not to disturb it too much. If you are upsizing, I recommend adding new sand to the tank and seeding it the sand from your old system. If you are downsizing, you can use your existing sand bed, but I recommend rinsing the sand in saltwater first to remove built up detritus. Or you can start with new sand and seed it with sand from your old system.

Go Bigger!

Maybe you started with an all-in-one nano system and, now that you're more experienced, want to hand-pick each piece of equipment. Maybe you want a certain fish, like a tang, that requires a larger tank. Maybe you've run out of room for your ever-growing coral. Or maybe you just want MORE. No matter what the reason, the one thing you know for sure is that you are ready to increase the water volume in your home.

Setting up and transferring the livestock
If your new setup is going in the same place as your old set up, you will need to either place the livestock in a temporary holding tank/container or carefully slide the tank and stand to a new location (if small and light enough).

Once the spot is clear—or, if the new setup is going in a different location—you can begin assembling your new tank. Ideally, you will already have set up the tank without water (the dry run mentioned earlier). This ensures the equipment all fits together and, if you needed to assemble any pieces, such plumbing return and drain lines, you have done so already.

  • If your new tank is doubling in size or less (for example, if you are upgrading from a 25 gallon to a 50 gallon), I have found one of the easier ways to accomplish the transfer is to simply move all the contents of the old tank into the new tank and top off with new, premixed saltwater of the same temperature and salinity.
  • If your tank is more than doubling in size, I have found setting up the tank fully and allowing it to run with new saltwater and any additional rock that will be in the tank for at least 4 weeks prior to adding your existing livestock is the way to go. Depending on the volume of the new system, you may want to add the livestock over a period of a few weeks to avoid any stress on the animals. Simply acclimate them to the new system just like you did to your old system.
  • If you are adding any type of new rock to the tank (live, base or dry), you can add that at the same time. Make sure you have cured the rock prior to adding it to the tank to prevent fouling up the water in your new setup.

After you have successfully transferred over the contents of your old tank into your new one and the equipment is running properly, I recommend not adding any new livestock for 3-4 weeks. You should monitor the new aquarium closely during the first few weeks to be sure the tank doesn't begin a "mini cycle." Everything should be stabilized in your new tank before adding additional livestock.

What should you do with your old equipment?

Now you might have an empty tank and equipment lying around that you aren't quite sure what to do with. Here are a few suggestions that will hopefully help solve this problem:

  • Sell it to a fellow hobbyist to help recoup some of the cost of your new setup.
  • Keep it running as a frag system. Selling homegrown frags helps reduce the hobby's dependence on corals from wild reefs plus will put extra cash in your pocket (this will again help you recoup the cost of setting up your new system).
  • Use it as a hospital/quarantine system for new livestock or sick tank inhabitants.
  • Donate it to a school. Many high school science programs have aquariums set up in their classrooms to provide students with a more hands-on learning experience.
  • Keep it running! After all, you can never have too many aquariums, right? Try setting up a completely different aquascape or grow some new life in a freshwater planted tank.

Going smaller: time to downsize!

The word downsizing has a negative stigma attached to it, especially in regards to employment. Fortunately, in the world of aquaria, downsizing isn't necessarily a bad thing. Nano tanks, once thought to be impossible, are now commonplace in the hobby. And, with all the advancements made in the last decade, they are easier than ever to set up and maintain. Plus, there are a variety of sizes and styles to choose from.

There are a few things you'll want to consider when moving from a large tank to a smaller one.

First up: livestock. The animals enjoying the spaciousness of your big tank may not be able to live comfortably in a smaller aquarium.

  • Fish
    Smaller fish, like gobies, blennies, some wrasses and clownfish may be fine, but fish that require larger systems, like tangs and many angelfish, will more than likely need a new home.
  • Coral
    You may need to do some major coral fragging if you have larger specimens in your big tank. You should begin with a few smaller frags of your favorite corals (if fragging is possible) to ensure they'll fit comfortably in their new home and have room to grow. I recommend fragging your corals a few weeks before you intend to move them so they'll have time to heal before the transfer begins.
  • Invertebrate
    Many types of shrimp, starfish, hermit crabs and snails will thrive inside a nano aquarium. But the number of members needed in a nano cleanup crew will obviously be less. You may need to thin out your cleanup crew a bit to ensure they'll all have enough food inside their new home.
  • Live Rock
    Cherry pick the best pieces from your existing aquarium to help aquascape the new one.

Once you have purchased your new system and are ready to make the transfer over, start by placing the live rock pieces you have chosen into the new system. After you have it aquascaped to your liking, you can begin transferring water from your old tank into the new one along with any other livestock that you will be keeping.

Next, turn on your new system's equipment (except for the lights) and make sure everything is functioning properly. Monitor the tank closely for the next few hours to make sure there are no issues and everything stabilizes. I recommend keeping the lights off for the day and slowly ramp up the photoperiod over the next few weeks to help your livestock acclimate to the new system.

Over the next few weeks, I also suggest doing some extra water changes to help keep a more stable environment. The moving and disturbing of the old tank's rock and corals could cause some die off of sponges or other micro and macro invertebrates and you will want to help minimize any possible fouling of the water.

Before you make the transfer over, please find new homes for any livestock that will not be staying with you along with your old system if you don't intend to use it in some way. Some possible options you can explore are finding local hobbyists to give, sell or trade your equipment and livestock with, donating it to your local fish club(maybe for a raffle or at an upcoming meeting) or talk with your local fish store to see if they might be interested in it.

No matter what reason you have for up or downsizing your tank, with a little bit of planning, you can make the transfer successful in a short period of time. Just make sure you give yourself plenty of extra time in case any unforeseen problems rear their ugly head.

If you have your own tips and tricks to share, please leave us a comment below. Thanks for reading!