Over the past ten years or so the marine fishkeeping hobby has begun to really grow. More people than ever are taking a look at this exciting area of the aquarium hobby and deciding that setting up a marine tank is not an impossibly large task, especially if reliable guidance is at hand. This two-part article will, I hope, inspire the unsure or as yet undecided into taking some positive action. Of course, some experience with freshwater tropicals is always an advantage, but you needn't worry if you are unfamiliar with keeping fish. We will cover all of the basics.
For many people, the technical side of the hobby holds no fears, and it is quite often external influences that decide our choices. For example, these days our lives seemed to be governed by space restrictions, most noticeably in the home. The rise of the affluent society has witnessed an unprecedented amassing of domestic "space fillers," such as larger televisions, home theater systems, wall units for music systems and computers...the list is almost endless.
Not that there is anything wrong in this, but when it comes to the humble fish tank it is often the space remaining that restricts our choices, rather than what is altogether correct for the animals that will call it home — not to mention what satisfies our creative capabilities. As a result, and all too often, the cry goes up, "But I've only got a few feet available, and I really want some lionfish and a moray eel!" In this case it really is impractical, but if we adopt a more pragmatic approach it certainly is feasible to include a modest marine aquarium in all but the smallest of spaces.
This can be an especially successful arrangement if the aquarium is limited to fish only. And, indeed, our discussion will be limited to tanks set up for fish. Reef systems, with their corals, are more complicated and demanding.
Most people can find the required wall space, even if it means rearranging a few pieces of furniture. Even a room divider arrangement can be practical and attractive. Of course, it will always be the case that a 2-foot tank is more convenient, but this size marine aquarium must be discouraged, at all costs, as a shortcut to disaster for the newcomer. This is because its holding capacity of less than a dozen gallons is inherently unstable in the long term.
Temperature, pH and salinity tend to vary wildly in such a small setup, leading to stress of the tank's inhabitants, disease and untimely deaths. Larger tanks have a greater buffering effect against such things.
I would say that an aquarium of 20 gallons is about the smallest that can be relied upon to give continued success, and even this size is really not recommended. It has to be said that some of the most impressive domestic marine aquariums range between 5 and 8 feet in length, but this sort of size is usually just too daunting for the newcomer, and is really quite unnecessary for good results. A 3- to 4-foot tank (about 30 to 55 gallons) is all that is required to get off to a good start.
Having found that elusive few feet of wall space, the aquarium and stand can be carefully chosen. A greater number of people these days are resisting the temptation to go for the all-glass tank with welded metal stand and plastic hood. While quite functional, it doesn't look like part of the decor when surrounded by polished wood furnishings. The cabinet style aquarium has become an increasingly more popular choice. It can be purchased in a wide range of finishes to complement almost any furnishing scheme, and has the added advantage of being able to conceal all those unsightly wires, pipes, pumps and canisters.
Having found an attractive style, the overall size can then be decided upon. The standard lengths available cannot be altered, but there are generally few restrictions on height and width (front to back). Taking into account what has already been said regarding the fact that larger tanks are more stable, why settle for a tank that is 36 x 12 x 12 inches (about 23 gallons) when a tank of 36 x 15 x 12 inches (about 28 gallons) or even 36 x 18 x 15 inches (42 gallons) will often fit equally well. The last example is actually greater in volume than a tank of 48 x 15 x 12 inches (just over 37 gallons).
Place the tank in a prominent position. All too often an aquarium is recommended to brighten up a dark alcove. The theory behind this suggestion seems very sound but in practice the unfortunate reality is that this nearly always leads to the "out of sight, out of mind" school of fishkeeping.
When an aquarium is out of the way, it is given a cursory glance once in a while and the all-important maintenance becomes unknown. Siting the aquarium where everyone can view it easily and in comfort for relatively long periods promotes a pride and enjoyment in fishkeeping (especially when high praise is heaped on the owners by impressed visitors). This, in turn, encourages that all-important vital regular maintenance, as we shall see.
Much has been written about various filtration techniques, and it is possible to incorporate nearly any one of these within, outside or underneath the aquarium. There has been some additions in recent years to the kinds of filters available, but traditional methods are still effective and often more reasonable in cost. One filter type that became more popular when saltwater tanks did is the trickle filter. These are not difficult to install and can be desirable from a water quality and maintenance point of view — more for fish-only tanks than reef tanks. A knowledgeable retailer can be a great asset in this instance, so don't be afraid to ask as many questions as you like. For our purposes, however, we continue to describe the most tried and tested methods.
Undergravel filtration, run in either the downflow mode with one or two matched powerheads, or in the reverse-flow mode utilizing a canister filter, is still quite acceptable. The traditional arrangement is to cover a filter plate (or plates) with a layer of coral gravel at a rate of about 10 pounds per square foot of base area. This is then covered with a plastic, followed by a layer of coral sand also at 10 pounds per square foot of base area.
Undergravel filters set up in this manner enable a good throughput of oxygenated water to reach the nitrifying bacteria that inhabit the sand and coral gravel, as well as providing a good buffering source to help maintain the pH of the water within the vital range of 8.1 to 8.3. Problems with the gravel bed clogging can be minimized by good maintenance practices.
Protein skimmers will not be familiar to the freshwater fishkeeper for one very good reason — they do not work very well in freshwater. For the marine aquarist, however, these devices have become an indispensable part of filtration. Put simply, they have the ability to remove large amounts of dissolved organic waste products, thus reducing the risk of overloading the biological filter.
In seawater, organic waste is attracted to any interface between air and water. These organics are called "surfactants" and can be seen as foaming scum that collects in the skimmer's cup. The protein skimmer takes advantage of air/water attraction by pumping thousands of air bubbles into a tube, thereby creating a huge surface area of air to which organic wastes can accumulate. The waste rises to the top of the tube and overflows into a collection cup, which is emptied at regular intervals. Many differing designs of protein skimmer are available, but the principal remains the same.
A canister filter packed with good-quality, marine-grade activated carbon is also considered essential, although aquarists using a protein skimmer sometimes prefer to use carbon perhaps one week per month. It adsorbs dissolved toxins and various dissolved compounds that can cause the water to develop a yellow tinge if they accumulate in the water.
Ultraviolet (UV) sterilizers are also valuable, although not as essential as protein skimmers. These devices pass the aquarium water close to a special lamp that has the ability to kill most organisms that come within range (about 6 millimeters).
Free-swimming stages of killer diseases, such as whitespot and Oodinium, are particularly affected, and, as a result, valuable fish can be largely protected without resorting to chemical treatments. The ultra-violet sterilizer is positioned preferably after the canister containing activated carbon. In this way, the somewhat clearer water is treated more efficiently.
At normal room temperatures a 100- to 150-watt heater for any of the tank sizes already noted would be quite sufficient. This can either take the form of the well-known glass tube type, or, alternatively, by the increasingly popular under-tank heating mat controlled by a remote thermostat. The main advantage with this method is that heat is more evenly dispersed throughout the tank and temperatures can be accurately adjusted externally without having to put a hand in the water. Apart from a small thermostatic probe, bulky electrical hardware in the tank is eliminated.
External thermostats can also be used to control internal heaters very accurately and conveniently. In the case of a heater that already contains a built-in thermostat, the internal thermostat control is adjusted to the maximum before connection to the external thermostat, which then takes over this function.
A good thermometer is also essential. One of the better quality alcohol-filled internal ones is ideal, although an external stick-on type would suffice if funds are limited.
Because we are setting up a fish-only aquarium, lighting will not be as crucial as it so often is with light-loving invertebrates. Two or three fluorescent tubes or two pendant mercury vapor lamps would all be equally acceptable.
Labor-saving devices such as a timers can be installed to switch the lights on and off at pre-set intervals. Several timers can also be used in tandem to control a variety of lights and to present a different atmosphere (e.g., moonlight), if so desired.
Lighting should be designed for the comfort of the fish as well as showing them off to their best advantage for human enjoyment. If doubt exists over the correct choice, then a visit to a good marine store could prove invaluable. The store owner should have a range of lights operating over the shops tanks for the hobbyist to make this sort of subjective decision.
Fish that are more common at greater depths or more active at night will prefer less intense lighting. Some of these species are also more likely to come out during the day if the lights aren't too bright.
Rockwork and Aquascaping
Both tufa and lava rock are very suitable for the marine aquarium, but each have various advantages and disadvantages. Tufa rock is relatively inexpensive and can help buffer the pH of the water due to its high content of calcium carbonate. However, it is fairly dense and displaces greater quantities of water.
Lava rock, on the other hand, is more expensive, does not influence pH, but is light and displaces relatively little water. A mixture of the two is often a good compromise. Other suitably inert rocks are also available, and should be considered for their cost and displacement qualities, as well as their aesthetic value.
Whichever rock is chosen, it should be arranged carefully and safely. Although many fish will enjoy swimming in and out of the rocky corridors, others will also require a fair amount of open space in which to swim.
Nearly all other natural rocks usually chosen for use in freshwater aquariums should be avoided, the only exception being slate. Many of these rocks contain harmful metals and minerals that would pollute saltwater and harm the fish.
Fishkeeping and conservation have become closer allies, and this is beginning to be reflected in the hobbyist's choice of tank decoration. On the way out are the stark white, dead corals, and on the way in are the artificial kinds made of inert colored resins These are often made by fishermen no longer able to fish the coral reefs and surrounding water, providing them with a valuable source of income where none would otherwise exist.