There are many pros and cons when it comes to purchasing large fish tanks. On the one hand, large fish tanks are easier to maintain and care for than are small tanks and fish bowls. On the 
other hand, large fish tanks are bulkier, heavier, and are more dangerous in areas that have lots of foot traffic. Owners of oversized aquariums need to insure that they are putting their tank on a professionally crafted stand, as well as in an area that can support its full weight.
The size that constitutes a large fish tank is typically any aquarium that is 50 gallons in size or above. When filled with water, sand, rock, and aquatic life, large fish tanks can weigh anywhere between 600 pounds (50 gallon tank) and 2100 pounds (180 gallon model) and should be placed in your home or office with considerable care.
When buying an oversized fish tank, the first consideration should be its placement. Because of the weight, bulk, and size of large fish tanks, they will need to be placed in an area (preferably next to a wall), that can provide the most possible weight support. You'll want to avoid putting a large aquarium in the middle of a room. This placement offers less floor support, a higher likelihood of the tank being knocked, cracked, broken, or pushed over by people or children walking by. The placement of the tank is one of the most important decisions you'll make when buying an oversized aquarium.
If you're considering the purchase of a large aquarium, it is also recommended that you meet with a professional builder or structural engineer who can help you best determine where to put your tank, and if you'll need to build any additional support. Their expertise can be invaluable when it comes to finding a location with suitable structural support issues and little foot traffic.
Another important consideration when considering buying an oversized aquarium is to be certain to also purchase 
a proper stand. It is particularly important with large fish tanks to purchase a professionally designed stand. Do yourself a favor and never build one yourself or use a makeshift piece of furniture unless you are a professional woodworker or metal craftsman and are comfortable making commercial-grade furniture. Buying the correct stand can make all the difference in the safety and stability of your tank.
Ultimately, the key when buying an oversized fish tank is to really focus on safety. Where will you be able to put the tank? Will it be in a location that has adequate structural support? Will it be safe from passersby? Bring in a professional, if needed, to help you determine these questions. Only then will you be able to be confident in your decision to invest in a large fish aquarium.
