Gone are the days of rectangle and square! The technology of today allows for almost any shape, size, design and layout that you can dream of. Custom aquariums can be built into bookshelves, around corners, under tables, and even as room dividers. While glass is still common and possibly lasts longer, acrylic aquariums are extremely popular due to their light weight and design flexibility. Although larger systems will cost more initially, remember that larger systems are less prone to temperature and water chemical fluctuations; something to consider for the long-term benefits before opting for the smaller systems.