Once thought to be far too difficult for mere mortals, a successful marine aquarium is now well within the grasp of any interested hobbyist. One of the biggest reasons for the increased emphasis on saltwater fishes and invertebrates in the aquarium hobby is that advances in aquarium equipment, coupled with advances in knowledge about marine biology, have made the keeping of marine animals of all types easier than it has ever been before. The tanks themselves are better, synthetic sea salts are better, filtration equipment is better, and lighting systems are better. These improvements add up to making it much simpler than it once was for aquarium hobbyists to reap the rewards that the marine end of the aquarium hobby can bring. Contents include mini-reef aquariums, modern aquarium practices, ecologically sound advice, filtration, lighting, protein skimming, water, fish-only marine tanks and compatibility. Jeffrey Kurtz is the author.