While glass might be the long time favorite due to tradition and an extended long term following. Goldfish tank owners who choose glass will say that acrylic scratches and is poor quality. While this may be true, acrylic does have many advantages over glass.

• Acrylic is 17x stronger than glass, softer and more flexible than glass. Acrylic is highly impact resistant.
• Acrylic weight about 50% less than glass, making a large tank easier to move. 
• Acrylic insulates 20% better than glass. This reduces temperature fluctuation and can save of heate, and chiller usage.

Acrylic Seams are different then glass as they are molecularly welded together. The resin used to seal them chemically will melt the two pieces together forming one solid piece that is virtually unable to leak.

Acrylic is also as clear as optical glass with a 93% transparency rating. Acrylic is known to pass the most light of any known material.

For these reasons most current public tanks are made from acrylic. While acrylic can scratch, scratches are easily buffed out without having to disturb the goldfish inside the tank. 

While many myths about acrylic have been laid to rest, some believe that acrylic can turn yellow and brittle over time. Do not confuse acrylic for plastic. Plastic may turn yellow and brittle but acrylic will not. Some people believe that acrylic tanks will bow and distort, but an acrylic tank made to specifcations will not do this. The one thing about acrylic that needs to be noted is the fact that acrylic is flammable. Your acrylic goldfish tank is not a good place for a candle. 

Domestic cell cast acrylic is the best type of acrylic for aquariums. Some of the brands of acrylic are:

• Polycast
• Rohm and Haas
• Cyro Acrylite
• Lucite

When looking for an acrylic tank, if the top is cut out be sure that the top width is the same as the side and bottom widths. Acrylic aquairum stands need to support the entire bottom of the tank to distribute the weight of the tank evenly. Special acrylic tools will need to be used when cleaning the tank.

I's true that glass tanks have played a historical part in goldfish keeping, and will continue to for those who remain loyal. Everyday more goldfish aquarists are turning to acrylic because of its many advantages.

Glass tanks may have ruled the past for goldfish tanks, but the present and future of goldfish tanks is in acrylic.