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Marine aquariumA Marine aquarium is an aquarium that keeps marine plants and animals in a contained environment. Marine fishkeeping is different from its counterpart freshwater fishkeeping in several important aspects. There’s more scientific bias in marine fishkeeping, the hobby of which is a large contributor to the vast scientific knowledge shared with the hobby.
Marine fishkeeping historyThe first personal saltwater fishkeeping began on a wider scale in the 1950’s , starting with the basic rectangular glass aquariums (usually 20 gallon), still popular today. Bleached coral along with a substrate of coarse crushed coral was the norm. Algae, including beneficial such as coralline, were viewed negatively and generally removed. The clean, sterile tank was viewed as the healthiest. During the beginning days of marine aquaria, saltwater was initially collected at local beaches. Natural saltwater contains many unwanted organisms along with the occasional unwanted pollutant. Aquarium literature of the time suggests that the most commonly kept marine fishes of the day were Percula Clownfish, Sergeant Major Damselfish , small brackish water puffer and scat , Jeweled Blennies , Sailfin Mollies, and Blue Damsels . Aquariums were equipped with large air compressors and were heavily aerated and filtered (primarily with underground filters , a norm for some time). Later in the hobby, air driven counter-current protein skimmers were invented and revolutionized in Germany along with the Eheim pump company. Perhaps the largest revolution in fishkeeping was a more reliable submersible electric heater, invented by Eugen Jäger . Even today, Jäger is still a major company in aquarium heating. Various initial aquarists attempted to find the chemical properties of sea water and mix in necessary trace elements to create synthetic salt mixes. Perhaps the first and undoubtedly the largest synthetic sea salt company was Instant Ocean . This revolutionized marine fishkeeping in landlocked areas instead of restricting it to areas near sources of seawater. Various advancements in filtration included the trickle and hang-on filters , both allowing more of a natural equilibrium to the aquarium environment. The advancement of fluorescent lighting technologies into higher outputs along with Metal Halide lighting established the reef tank, making it a possible to keep corals and invertebrates without natural sunlight. More efficient chemical testing and more advanced knowledge allowed aquarists to have an idea about the chemical conditions and properties of aquariums. The biological establishment and understanding of maintaining an artificial ocean environment brought more successful and widespread marine fishkeeping. In the 1980’s, numbers of aquarium publications had greatly increased, and general chemical and biological knowledge was more widespread. Modern fishkeepingThe major components of a tank are the tank itself, a stand, filtration, lighting and heating. Tanks can range anywhere from a tiny nano reef tank to gigantic 300 US gallon (1200 L) tanks. Nano tanks are usually between 2.5 and 20 US gallons (10 and 40 L), though some definitions include tanks as large as 30 US gallons (120 L). These tanks are difficult to maintain due to the highly variable chemical properties of saltwater. It is simply easier to make mistakes with a highly concentrated body of water. However, a truly monstrous tank can be difficult to maintain simply for sheer bulk. For this reason, most saltwater tanks are between 40 and 100 US gallons (160 and 400 L). The stand is usually made of wood: fish tanks filled with water are extremely heavy and needs a very sturdy base. The weight in mind when setting up a tank in an apartment that is not on the ground floor. The new age of fishkeeping focuses on various components functioning in order to create a biologically stable environment. There are various orthodoxies of fishkeeping today. The basic varieties of tanks are Fish Only (FO), Fish Only with Live Rock (FOWLR - arguably the most popular) and the reef tank, containing corals, sea anemones, or other delicate invertebrates. Live rock is rock that has been in the ocean, usually around a coral reef such as thouse around Fiji, and is usually covered with beneficial algae, coralline and tiny invertebrate cleaners that are desirable in the aquarium. Some examples of the microfauna commonly found on live rock are crabs, snails, feather dusters, brittle stars, sea stars, limpets, abalones, and an occasional sea urchin, anemone, coral or sponge. Bristleworms are also used, most of which, while unattractive, are not harmful and are useful scavengers; some species can be pests, however. The addition of live rock is one of the best ways to ensure a healthy aquarium, as the rock provides a buffer for good pH (8.0-8.3) and carbonate hardness (KH), the microfauna are detrivores and herbivores (eating algae and fish waste), and provides fish with a natural, attractive shelter. It usually arrives from online dealers as "uncured" and must be quarantined in a separate tank while undergoing a curing process. Live rock that is already cured is available at most pet stores that cater to saltwater. Live sand is similar to live rock and is equally desirable. Liveaquaria.com (see link below) has some good information about different kinds of live rock and the curing process. There are innumerable filtration methods available to the modern aquarist. They will all use a combination of chemical, physical and biological filtration. The common trickle filters that hang on the backs of aquariums are usually only physical filters, which are not enough for the saltwater aquarium, though some have plates where bacteria can colonize and provide biological filtration as well. These plates should never be cleaned, as this would kill the bacteria colonies. Most filters will say on the box which methods of filtration they utilize. Depending on what is in the tank, protein skimmers are also very useful in the reef tank. With a low bioload (not many animals in the tank) and hardy livestock, a protein skimmer may not be absolutely necessary, though it is never a detriment. A heavily stocked tank, corals, and other delicate animals may need a protein skimmer to survive. Perhaps the most popular and widespread biological filter is the refugium. Water is drawn from the main tank to the refugium (usually a smaller container hidden behind or below the main aquarium), then is returned to the main tank. This little tank serves two purposes: it adds water volume (thus diluting any chemical problems) and it provides a place for LOTS of biological filtration. They can also serve as a temporary shelter area for recovering injured fish, delicate animals that need to be slowly acclimated, and to temporarily separate fighting inhabitants. Refugiums often contain live rock and live sand, macroalgae, and scavenger microfauna such as micro brittle stars, tiny sea stars such as asterina , snails and worms. Some people also use refugiums to raise tiny brine or mysis shrimp for delicate fish like seahorses and dragonets. A sump is a refugium that also contains the main aquarium's other equipment to keep all the hoses, filters and heaters out of view. This is especially common for show tanks and reef tanks. Lighting is a controversial topic in fishkeeping. Most fish aren't particular about lighting - the light is more for the aquarist than for the fish, though a cycle of light and dark, simulating day and night, is beneficial for them since it establishes a routine and makes them feel more secure. Any light will do for an FO tank. A FOWLR tank will need a more powerful light, however, since algae and coralline need light to grow. There are many types of lights available; generally speaking, the higher the power rating, the better. Some types include fluorescent, VHO (Very High Output), and metal halide. A powerful fluorescent may be enough for a FOWLR system. Coral reefs require very powerful lights and specific spectrums; research particular species' needs before buying. Metal halides seem to be the most popular for coral reefs. Most fishkeeping is tropical, and most fish gathered are caught in Africa, Southeast Asia, and the Red Sea. A temperature of 75 degrees Fahrenheit to 82 degrees Fahrenheit is most common, reflecting the environment of the organisms. This necessitates the use of a heater, almost always fully submersible. Cold water marine fishkeeping is generally only regional, and most cold water fish are caught locally. This is because the physical appearance of cold water fish is not as attractive or colorful as its tropical counterpart. A test kit is also a valuable tool in fishkeeping. The most common things to test for in a saltwater aquarium are: 1) specific gravity or salinity - usually between 1.020 and 1.025 for fish, and 1.023 and 1.025 for invertebrates and corals; 2) pH - between 8.0 and 8.3 (can be raised with a commerically available buffer); 3) carbonate hardness (KH) - between 8 and 12 (measures the trace elements and minerals in the water - raised by pH buffer); 4) the ammonia cycle - ammonia, nitrite and nitrate. Fish waste and decaying matter release ammonia, which becomes nitrite, which becomes nitrate, which is then absorbed by algae, bacteria or just hangs around in the water (hence why algae is not all bad.) Sounds gross, but it's just what happens in every fish tank. Ammonia and nitrite should always test to be zero. It's normal to have a little nitrate buildup, and some livestock handle it better than others. Some invertebrates and most corals do not tolerate nitrate, and no marine animal does well at higher levels. It's best to keep nitrate as low as possible by having a low bioload and carrying out regular water changes. Other tests may include testing for calcium, iodine and othe trace minerals. Research the particular species you wish to keep to see if it is necessary for you to do additional testing. Water changes are a staple of good saltwater maintenance. It involves removing 10 to 20% of the water in your tank and replacing that water with pre-mixed fresh saltwater. For instance, with a ten gallon tank, mix one or two gallons or water in a jug with a synthetic saltwater mix, like Instant Ocean. Add a drop of chlorine remover if using tap water. Check with your utility company to see what your tap water contains. In almost all places, tap water will be too contaminated with chemical and purifiers to be used in a saltwater aquarium. You will most likely use distilled water instead. Look for water made using reverse osmosis (RO). Let the mixed water sit about a day to let everything dissolve. Check the salinity with a hydrometer to make sure it was mixed right. Remove one to two US gallons (4 to 8 L) of water from your aquarium and pour in the premixed saltwater (gently - try not to disturb your sandbed if you are using sand, because it's a big mess!) The next day, check your salinity. This is a very basic description of a water change - depending on your setup, you may need to include certain additives or buffers. Most aquarists develop a schedule of maintenance for their aquarium. A possible schedule might look something like this. Daily: feed fish (once, twice or even more depending on species - never overfeed, as it will cause an ammonia spike), turn lights on and off, check livestock for signs of health, check equipment is on and running well, check temperature, top off tank with freshwater to replace evaporated water. Weekly: test water, change 10 to 20% of water with premixed saltwater, add pH buffer or other additive as needed, remove salt creep from filter or other equipment, wipe down glass, scrape algae from the glass of the tank (after all, it's nice to be able to see all these nifty critters!). Monthly: change filters (more often if you have a high bioload.) Remember, this is a VERY basic list of chores for a simple system, and is only intended to give an idea about the level of care needed for a saltwater tank. Certain species or setups may need more attention. Marine animals today are nearly exclusively caught in the ocean, such has brought controversy. Common practices of collecting fish may involve cyanide, which destroys and poison reefs; however the use of cyanide is small and generally portrayed out of proportion. The collection of marine animals has also sparked some Southern Asian and African countries as being a profitable industry. Various businesses have brought a commercial front to fishkeeping, perhaps the largest being Marineland, Inc. Along with movies such as Finding Nemo, fishkeeping is becoming much more widespread than ever before. Perhaps the biggest turndown in fishkeeping is the initial costs. A 100 US gallon (400 L) reef tank full of coral and equipment often costs upwards of $5000 US. Aside from the difficulty, this is a large factor as to why freshwater fishkeeping is still so widespread in comparison to its marine counterpart. References and further reading
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