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  • Writer's pictureStewart Kessel

Second-Hand Fish Tank - Bargain or Mistake?

Updated: Jan 8

Are second-hand aquariums a shrewd, money-saving move or something you may regret?

Purchasing a new aquarium, especially a large one, can be very expensive. Therefore, the prospect of a second-hand aquarium, maybe with included equipment, all at an attractive price, might be something that you just can't ignore. Perhaps you are even fortunate enough that someone is gifting you an aquarium.

What should you consider when looking at a second-hand aquarium?

Let's consider some of the more obvious pros and cons of purchasing, or being gifted, a second-hand aquarium.


Quicker access into the hobby (more affordable)

Lower cost – more money to spend on the fish!

Often has other equipment included 'free of charge' (see later note)


No guarantees

Cosmetic damage (glass scratches & chips)

Potential for hidden costs

The advantages of a second-hand aquarium understandably all centre around, making ownership more affordable. There is no denying that purchasing a new aquarium, especially a larger capacity tank that we often recommend, can be a significant outlay of money. And as a consequence of the larger tank size, the bigger the capacity of filter and heater that will be required, and the more substrate and décor that will be necessary – all adding to the expense.

Therefore, a second-hand tank, offered at a fraction of the cost, including lots of the additional required equipment, sounds like a no-brainer.

However, you need to consider the consequences and potential hidden costs carefully. A second-hand tank, by its very nature, will not come with any guarantees. You will need to test and ensure the tank is watertight, preferably in a location away from where any costly damage could occur if the tank leaks or, at worst, bursts.

It is difficult to determine the expected life span of a silicone sealed aquarium. There are too many variables. Not least has the tank been handled with due care. Manufacturers will suggest that the silicone sealer is good to last for 10-15 years. Indeed, I have previously had silicone sealed aquariums in my fish house for 15+ years without issue. However, I have equally seen instances where previous owners have been too vigorous in an attempt to clean up an aquarium for sale and, as a consequence, have damaged the sealer.

Cosmetic damage such as scratches on the aquarium glass will not affect the longevity of the aquarium but detract from visual pleasure. Chips on the glass, particularly on the base plate edges and bottom corners, are much more of a concern and could lead to failures. Damage to the bracing bars (where fitted) would also be a cause for concern. So, the advice is to carefully inspect and check the aquarium's condition when making a purchase decision.

A used aquarium will inevitably need cleaning before use. Before filling up with water is an ideal time to clean away any grime and build-up of limescale deposits, especially for aquariums located in a hard-water area. It is best to use specialised aquarium cleaners or, in the case of limescale white vinegar, but take care not to use anything abrasive and remember to rinse out the aquarium thoroughly. Although this clean-up is relatively easy and rewarding, it can also be very time-consuming and could identify defects not previously seen. As mentioned earlier, to avoid damage, be especially careful when cleaning the silicone sealed joints.

A bonus when purchasing a second-hand aquarium is that often the seller is willing to include other necessary equipment free of charge. But again, take care as not everything might be as it seems. Faulty equipment could bring additional unwelcome costs, not only with replacing them but also with any damage they might cause. By way of example: Aquarium heater/thermostats are notoriously easy to damage if stored or transported incorrectly – care as we all know, water and electricity do not mix! Filters, in particular, external canister filters, if not in use and left un-serviced can, for example, spring leaks due to dried out and perished gaskets.


The second-hand market is undoubtedly a route to obtain attractively priced aquariums, and for some, it perhaps offers the only affordable path to get into the hobby.

If you decide to purchase a second-hand aquarium, our advice is to ensure you check the condition of the tank thoroughly and confirm it is watertight. Test any equipment to verify correct operation. Be mindful of how easy and how long it will take to clean the aquarium. But ultimately enjoy the process of setting up, owning and experiencing the joys of fishkeeping.

For further fishkeeping advice, read our other introductory and set-up guides at

Author: Stewart Kessel CChem, MRSC

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