Although aquarium keeping is, by and large, a pleasant and harmless endeavor, there are a few precautions that you should keep in mind when pursuing your hobby. A few basic safeguards put in place early on will save you a good deal of time, trouble, and expense.

Do not ignore basic electrical safety in your rush to provide your pets with ideal captive conditions. Especially where large systems are concerned, an electrician should be consulted to make sure that the equipment you plan to use can be supported by your home's electrical circuitry. Electrical appliances should be operated and installed only as directed by the manufacturer's instructions. (Resist the temptation to experiment with installing electrical appliances yourself!) Likewise, make sure that any extension cords that are added to your system can support the appliance to which they are connected. Some aquarium lights give off a surprising amount of heat, so you must be certain that they are kept away from anything flammable. Lights mounted over aquariums must be securely fastened so that they do not fall into the water, creating an electrical hazard. Be certain, also, that the fixtures in which your lamps are installed can support the wattage of the lamp.

Even small aquariums are surprisingly heavy when filled with water and gravel. Be sure to calculate the weight of your aquarium and make sure that the floor below it will support that weight. Also, make sure that the stand or furniture upon which your aquarium will sit can manage the weight of a full aquarium. Floods, especially those caused by large aquariums, can be devastating in terms of property damage to you or your neighbors.

The world's fresh and marine waters are well stocked with venomous creatures. As will be mentioned in the various species accounts, the barbs and spines of many species of fish are connected to poison glands, some of which can inject fatal doses of venom. Venomous invertebrates abound as well, and even the highly toxic blue-ringed octopus is offered for sale from time to time.

Avoid keeping venomous animals, even though they may be offered for sale and may appeal to your sense of adventure. Be aware also that not all of the venomous creatures that exist have been identified — some may be unintentionally or unethically offered for sale. Therefore, err on the side of caution in purchasing or handling animals with which you are unfamiliar. Two well-known herpetologists lost their lives after being bitten by snakes formerly believed to be harmless; do not repeat those tragic blunders with your own pets. There are literally millions of bizarre and interesting aquatic creatures that can be kept safely. Think not only of yourself, but of the potential for accidents involving unknowing or reckless individuals as well.

Aquatic animals and the water in which they live may harbor microorganisms that are harmful when ingested by people or upon entering a skin wound. Therefore, never clean aquariums or related utensils in sinks that you use to prepare food. Always wash your hands thoroughly after working with your aquarium, and be particularly careful with children. In addition to washing their hands, you must be alert that they do not put anything into their mouths that has had contact with your aquarium or its inhabitants.