There are a lot of used aquariums for sale as many people bounce from the fishkeeping hobby. Also, with the increasing cost of aquariums, buying a secondhand aquarium could be a golden opportunity for people who love fish-keeping.

But many of you may wonder will is it worth the risk to buy a used aquarium and how to find a genuine product for a good price. Let’s dive in.

Where can you find Second-hand fish tanks for sale?

So the first thing you need to know about buying a second-hand aquarium is where to find a good deal. There are several options for you to check used aquariums for sale near you.

The first place you can look for is at your local fish store. Many local fish stores will sell used aquariums from some of their customers, and it’s a great place to find lots of different options.

But the downside of buying used aquariums at the local fish store is that’s probably where you’re going to pay the highest money. So if you don’t find any good deals from there, the next option is to start looking at social media and some of those online sites that sell used items.

You can check used fish tanks for sale on craigslist, Facebook marketplace, eBay, and many other related online platforms. Especially the second-hand fish tanks for sale on eBay and Facebook marketplace can be easily filtered with your location and you can get detailed images of the tank before you visit.

Used Aquariums at Facebook Marketplace
Used Aquariums at Facebook Marketplace

Now, if you can’t find the fish tank that you want or if you can’t find something at a good price on those online options, another option you could try is to go to a local yard sale group or something similar on Facebook. Just put your requirement out there and people who want to get rid of their old fish tanks will respond. 

How do you inspect a Used Aquarium?

So once you’ve found the fish tank you want, the next step is to go ahead and evaluate that fish tank. 

Check for Glass Cracks, Chips, or Scratches

The first thing you want to check with any used fish tank is the glass whether there are any cracks in it. Obviously, if there are any cracks, it’s not going to hold water. 

You definitely want to take a close look at the edges of the tank as well. There may be little chips on the glass edge of the tank. A small chip is okay, but if it starts to get into the silicone seal or gets close to the silicone-glued seal, that’s a tank you’ll want to pass on.

Check for Leakages and Damages Silicone

Then keep moving along the silicone seal to check whether there are possible leaks. If you see any dark spots inside the Silicone seal, it can be a sign of leakage. Really those spots are, where moisture has gotten into the seal, and no more bond between glass and silicone.

Dark spots inside the Seal of Used Aquariums
Dark spots inside the Silicone Seal

Another way to inspect the Silicone seal is to run your fingers along the Silicone sealed edges and see if it peels up easily. If it peels, the Silicone glue is probably getting old that will look almost white in color. It’s probably worn away on the edges and look’s kind of just really thin.

Weak Silicone seal of Used aquariums
Weak Silicone seal of a Used aquarium

Other Things to Check When Buying a Used Aquarium

In addition to the fish tank inspection for cracks and leakages, there are some other factors to check before buying a used aquarium.

How long does it keep Dry?

The time that an aquarium is kept without water should be considered. Because Silicone seams can tend to shrink over time and might result in the formation of leaks that were not initially present but have emerged as a result of prolonged storage.

What Kind of Fish Were Last Kept?

You should find out what kind of fish were housed in that aquarium most recently and whether any chemical treatments were applied for any disease or something else.

Because there are some serious diseases and virus infections such as KOi fish sleeping disease that can persist in even a dried aquarium.

Should I reseal a Used Aquarium?

If the silicone seal of the fish tank is damaged or old, just plan on resealing it. If you don’t feel comfortable resealing that used aquarium, you should probably walk away. Otherwise, you are risking your fish. Even though it doesn`t leak at that time, it may start leaking later. 

However, a bad seal job or an old seal isn’t much worse, if they are for a reasonable price. You can easily repair and reseal your aquarium at home with simple tools like a cock scraper, a cock gun, and some silicone. It’s pretty easy to do

Aquarium resealing
Aquarium resealing

Is it Worth Buying a Used Aquarium?

Generally, if you’re going to buy a used aquarium, it is recommended to get at least 55 gallons or larger because smaller tanks are not much expensive. You can buy smaller fish tanks even at the dollar-per-gallon sale at Petco with a warranty. So you don’t have to worry about smaller used aquariums.

There are lots of fish tanks out there for free and at low prices. Sometimes there are good deals for fish tanks with all sets of other aquarium equipment including aquarium filters and decorators. Hopefully, these tips will help you to inspect a secondhand aquarium and make an informed decision on whether or not you should buy a used aquarium.


I am Prasanjaya who is an aquarium hobbyist for nearly a decade. I wish to help fishkeepers to get accurate and helpful information regarding every aspect of fishkeeping.

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