Setting Up Marine Tank
A modern all-glass tank is ideal for marine fish, and there is no point in trying to use other types. Metal-framed aquaria are obviously too hazardous and all-plastic tanks, although initially attractive, soon become scratched and discolored. Remember that, the larger the tank, the more stable will be the habitat it contains. Moreover, because of their high oxygen demands, marine fish cannot tolerate any degree of crowding. Except for tiny fish, a tank of about 75×50x30cm (30×20x 12in) should be the minimum, and a tank about twice this size is preferable. The tank should be deep, as marine fish do not usually live only at the surface, and spend as much time swimming vertically up and down as they do swimming along the tank.
The tank can be installed as for freshwater aquaria. When you position it, remember that any spilled sea-water will cause more damage to carpet or furnishings than tap water, so be very sure that you can fill or empty it without risk of domestic damage.
A close-fitting glass cover is essential. Not only will it prevent fish from jumping out (although marine fish are less likely to do this than freshwater fish), but — most importantly — it will reduce evaporation of the water, which would cause drastic increases in salinity.
It is obviously impossible to avoid the use of metal in the light-in hood, but great care must be taken to ensure that any condensation cannot drip back into the tank. Use of fluorescent tubes is very important, as these can provide the bright light, rich in ultraviolet, which the fish need for health, and under which theircolours can best be seen. Use the largest single fluorescent tube you can fit into your lighting hood. As a rule of thumb, it is normal to allow 30 Watts per 900cm2 (140sq in) of the tank’s surface area (length x breadth). There is little harm in having too much light: it’s unlikely to be more intense than that in the natural habitat of the fish, and will cause algae to grow; marine fish graze on algae, and the algae also help neutralize the fishes’ toxic wastes. Most aquarists prefer to use the special horticultural tubes sold under various brand names, which not only encourage algal growth but also greatly intensify the colors of the fish.
The marine tank can be positioned where it will receive reasonable amount of natural light (but not direct sunlight). Once again, this additional light improves growth and will not disturb the fish.