There are some really stunning marine aquariums to be seen nowadays. Some of them are big, some are small and some are very small. In the big aquariums the beauty is probably mostly in the impact on the eye. In small and very small aquariums the beauty is probably more in the detail. They all have in common Mother Nature’s life forms in all their variety and colours.
There is something else that all successful marine aquariums have and that is environmental stability. This simply means that the different levels that are maintained with various items have little variation. Some of this is achieved automatically, some with the assistance of the aquarist.
There isn’t any intention of going into the full list of all the parameters that could be present as different systems – fish only and reef – vary. This is not to say that it doesn’t matter so much in one system or the other with parameter stability as it does. However, the reef aquarist needs to pay more attention to more parameters than one with a fish only system.
Some common examples won’t go amiss however. Temperature is important and the selected temperature should not vary unduly. This is commonly maintained by a heater/thermostat where the variation could be +/- 1 deg F. The seawater specific gravity should not vary measurably over a short period. The problem with seawater is it evaporates, or at least the water content does leaving the salt behind. Therefore the salt content has a tendency to rise and this is prevented by an auto top-up system or a manual top-up by the aquarist, the latter usually needed daily. The lighting and the lighting period may not seem like a parameter in the usual sense but stability is required with this also. With a reef system it is important that the spectrum and intensity are correct so bulb and/or tube changes are required periodically. Common to fish only and reef systems is the ‘lights on’ period. Whatever the individual aquarium requires, it should be regular and controlled by electric timers. This provides the livestock with a day and a night which they become used to. To enhance this, many aquarists include a ‘dawn and dusk’ cycle using the blue actinic fluorescents that are often fitted. These are set to come on ½ hour and go off ½ hour before and after the main lights turn off. As said there are more parameters, mainly to do with the seawater.
Stability is required because marine livestock could be said to be the spoilt children of Mother Nature. Disregarding the pollution and other damage caused by mankind, the wild reef is a stable environment. The reef is washed by the sea and oceans where volume is measured in cubic miles. The parameters of the seawater hardly change because the seas and oceans are so huge. There may be very short term changes in salinity at the surface during and for a short time after a heavy tropical rain storm and there may be some variations in temperature according to the time of day but overall stability rules. The life forms on the reef have adapted to this over a very long period indeed and they are hardly able to change quickly to a new environmental situation. That is why it is so important that new livestock are acclimatized properly to home seawater, which enables them to have at least some adaptation time. It is remarkable that livestock survive so well when they have faced the stresses of travel and an introduction to more than one holding tank on the way.
Compare the stable environment of a marine fish to that of a freshwater one in an ordinary small slow moving river. The freshwater fish is subject to more temperature change as the low water volume is more easily affected by the sun. If there is heavy rain then the water flow will increase and at the same time run-off into the river of soil will cause quality reduction of the water purity. In times of drought the river may reduce to a trickle and be even more subject to temperature and quality variation. Fresh water fish survive all these variations – in fact, the ability of different species of freshwater fish to survive extreme variations is remarkable. They have of course adapted to their environment in the same way as marine species have adapted to theirs.
The marine aquarium as said presents a lovely picture, usually fascinating to the non-aquarist as well. The beautiful and diverse livestock that could be present all depend on a high quality stable environment.