What to consider when setting up a salt water aquarium

The Financial Considerations - How much does it cost? Some Special Considerations Concerning Invertebrates
The Biological Considerations Suggested Reading
The Ethical Considerations Symbiosis

Coral reefs represent one of nature's most diverse and spectacular ecosystems; no wonder so many people want to keep a small part of this amazing ecosystem in their homes. The myriad of brightly colored organisms that inhabit today's tropical oceans are the result of millions of years of evolution. Flourishing in the stable conditions of this environment are organisms that are extremely well adapted to a narrow range of conditions. This unfortunately makes it more complicated and expensive to successfully maintain these organisms in captivity.

The purpose of this page is to introduce prospective marine aquarists to some of the time commitment, ethical considerations, and financial responsibilities associated with the maintenance of a marine aquarium.

The Financial Considerations - How much does it cost?

Ask yourself the following initial questions:

1. How big of an aquarium do you want? You might think the bigger the aquarium, the bigger the problems. Actually, a bigger aquarium is often easier, because the larger volume serves to reduce environmental fluctuations. You should think about getting the biggest tank you can afford to buy and maintain.

2. What kind of organisms do you want to keep? You don't need to pick out specific species, but give at least some thought to the type of organisms you might want to keep. Do you want fish only, invertebrates only, or fish and invertebrates together? Fish alone are the cheapest and simplest to buy and keep; fish with invertebrates are the most expensive and complicated. These considerations will also help you decide how large an aquarium you should get.

Keep in mind the organisms themselves can be quite expensive. Except for a few species, the vast majority of fish and invertebrates commercially available are taken from the wild. Most of the organisms are sent to the U.S. via air cargo from places like the Philippines, Fiji, and the Solomon and Marshall Islands in the Pacific. You can expect to pay in the range of $15 to $150 per specimen regardless of its source.

3. How much time are you willing to invest? At a minimum, you need to spend some time everyday feeding and observing the organisms, monitoring temperature, and checking on pumps, lights, filters, etc. You also need to routinely test various water chemistry parameters (salinity and pH for example), perform water changes, do any upkeep on your filter(s), etc. The size of the aquarium and the organisms you decide to keep will influence how much time you need to invest daily, weekly, monthly, etc.

4. What supplies and equipment will you need? That depends greatly on aquarium size, organisms, and time investment, but the following should serve as a general guideline.

a. If you decide to set up an aquarium in the 30 to 130 gallon range for fish only, here are some of the things you will need, as well as what you might expect to pay for them:

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Initial investment $550 - $2,000

That does not even include any fish yet. After the initial investment, expect annual expenses (food and supplies mostly) to fall between $50 and $250.

b. If you decide to set up an aquarium in the 30 to 130 gallon range for invertebrates only, here are some of the things you will need, as well as what you might expect to pay for them:

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Initial investment $1,820 - $6,500

That does not even include any invertebrates yet. After the initial investment, expect annual expenses (food and supplies mostly) to fall between $125 and $400.

The Biological Considerations

Good water quality is essential to maintaining a successful marine aquarium. Marine organisms excrete highly toxic ammonia into their environment, which is consumed by specialized bacteria and ultimately released as less toxic nitrates. Most of the conventional filtration systems (undergravel, canister, and wet/dry or trickle), do little more than increase the surface area available to these bacteria. (These same bacteria also inhabit the substrate, rocks, and decorations in aquariums.) The nitrates themselves can be toxic if allowed to accumulate, adversely affecting the invertebrates first, then the fishes. To keep nitrates from climbing to dangerous levels, most aquarists find it necessary do a 10% to 20% water change every month.

An alternative method of limiting the buildup of nitrates in aquariums (as well as ammonia, nitrite, and phosphate) is to use algae. All of the aquaria in the Exploring Marine Ecosystems Exhibit utilize algal turf scrubbers to remove excess nutrients. Algal turf scrubbers provide an ideal habitat for the fast growing, filamentous algae (sometimes known as hair algae) that is excellent at removing excess nutrients as it photosynthesizes. The algae is routinely harvested, which promotes the uptake of these nutrients. As a result, these compounds are kept at near natural levels, without the need for water exchanges. Growing macroalgae in an aquarium will also help to maintain low nutrient levels, but it may be necessary to routinely remove some of the algae to keep it from overgrowing the aquarium. For more information on the algal turf scrubber technology you can read Dynamic Aquaria by Walter Adey and Karen Loveland, for sale in the museum shop.

In addition to excess nutrients, marire organisms excrete organic compounds that, in the absence of proper filtration, will accumulate in an aquarium. Many species of algae and invertebrates produce these compounds to defend themselves from being eaten and/or crowded (a kind of chemical warfare if you will). Excess organics cause the aquarium water to turn yellow and adversely affect important water quality parameters. There are a few reliable ways to remove organics; the use of activated carbon is efficient and relatively inexpensive. Filters known as protein skimmers are designed specifically to remove organics as well, but they are more expensive (see "Financial Considerations").

It is a bad idea to use tap water in a marine aquarium, since most tap water contains higher levels of lead, iron, copper, phosphate, ammonia, and nitrates than normally found in nature. Many of the algae problems that plague marine aquarists can be traced back to their use of tap water with its excess nutrients. Whenever mixing new salt water for a water exchange or replacing water lost through evaporation, it is a good idea to use purified water, which can either be purchased (at the grocery store) or produced at home with a good water purification system for around $125 to $300.

A common pitfall of new, and sometimes experienced, marine aquarists is overcrowding the aquarium. Salt water fish require more space and better water quality than most fresh water fish, and no matter how tempting, that means having fewer fish in the aquarium. Plan on keeping about one inch of fish for every three to five gallons. That means that a 30 gallon aquarium should only contain three to five fish that are two inches in length. Also keep in mind the fish's weight; a heavier fish will eat more and produce more waste than a thin-bodied fish the same length. The number and kind of fish you keep is directly related to your filtration system's ability to deal with waste products produced by the fish. Remember -- limiting the build up of waste products in an aquarium is generally an aquarist's biggest challenge.

Overcrowding in an aquarium not only threatens the water quality, it may also stress the organisms, making them more susceptible to parasites and disease. This is especially true for fish. Treatment of the some common fish ailments is problematic because the most effective medicines interfere with biological filters and are toxic to many invertebrates. Try to avoid problems by inspecting new specimens closely for signs of parasites or diseases. Isolate and, if necessary, treat new fish in a quarantine aquarium for at least two weeks before adding them to your display aquarium. You will find that it is easier to treat new fish before you introduce them to the aquarium than it is to try to catch them out of the aquarium to treat.

Many marine fish defend territories and will respond very aggressively when they feel threatened or overcrowded. On the other hand, some fish live in social groups and only do well if there are others of the same species present. One way to avoid overcrowding is to keep fish that occupy different niches; for example, have some fish that swim in the water column, some that dart among the rocks, and some that live on or in the substrate. Don't forget to be on the lookout for species that will make meals out of their tank mates. It could be a very costly dinner - for both you and the fish that got eaten.

Some Special Considerations Concerning Invertebrates

There are two types of corals - those that secrete a hard, calcium carbonate skeleton (hard corals) and those that don't (gorgonians and soft corals). The latter usually, but not always, secrete a soft, flexible skeleton. The polyps (the individual animals) of both kinds of corals live as a colony inside these skeletons. Over thousands of years, the process of hard corals building their skeletons (known as calcification) on top of the skeletons of old corals forms the reef.

Many corals, anemones, and clams possess symbiotic microscopic algae within their tissues which facilitate calcification. These specialized algae, called zooxanthellae (zoo-zan-thel-ee), use light and wastes produced by the animal as they photosynthesizes. The algae then "share" the sugars they produce with the polyps.

The unique characteristics of corals and other invertebrates make them appealing to many marine hobbyists. Most invertebrates, however, have special requirements that make them more difficult to maintain than fish. They are generally more sensitive, tolerating less environmental change than fish. In addition to the basic necessities, invertebrates such as corals and many sea anemones require increased lighting, filtration, and water flow. For many invertebrates, these special requirements facilitate their relationship with the symbiotic algae. In order to more easily meet these requirements, it is usually easier to have an invertebrate only aquarium, and not try to combine invertebrates and fish.

The special requirements of invertebrates require the investment of more time and money in care and maintenance. You need to pay increased attention to various water chemistry parameters such as pH, trace elements (calcium in particular), alkalinity, and the levels of dissolved organic compounds and nutrients. This means testing several parameters regularly, adding trace element solutions regularly, and most likely cleaning a filter and/or doing regular water exchanges. You should not even consider keeping invertebrates if you are not willing to spend the money for proper lighting, pumps, and filtration, none of which are cheap. You will most likely need to purchase one to three pounds of what's known as live rock, rock collected from the reef in which the necessary bacteria thrive. This live rock will serve as a kind of filter, reducing your need for outside filtration. It can cost anywhere from $5 to $15 per pound.

Corals, and invertebrates in general, are delicate creatures. More and more are being collected from the wild, in part to replace the ones that die routinely in people's aquariums. Remember that hard corals are responsible for building the reef, so the fewer the hard corals, the slower the reefs will grow. Soft corals and gorgonians generally do better in captivity than hard corals, so if you want to have corals, think about keeping them. Also, because soft corals and gorgonians do better in captivity, they are easier to culture in captivity. It is therefore possible to purchase tank raised specimens instead of wild caught ones. This is a good idea when buying any kind of specimen (see the following section, "The Ethical Considerations"). Whatever kind of coral you buy, make sure it is one that possesses the symbiotic algae and can for the most part feed itself.

The Ethical Considerations

Today's aquarium hobby, especially salt water, is a large, lucrative business. As with anything, there are those who are in it purely for profit, with little regard for the environment. These people range from the collectors who still use cyanide to catch fish, even though it shortens the fish's life, to the retailers who will sell anything to anyone, no questions asked. In between, these delicate creatures are at the mercy of an airline industry which does not afford them any special treament or priority. It is not unheard of for a marine wholesaler to receive a shipment where all or nearly everything has died in transit.

The aquarium industry needs to make a number of changes to reduce its impact on wild coral reefs. Breeding organisms in captivity is the best way to reduce that impact, thereby reducing the amount and kind of species taken from the wild. Unfortunately, nearly all coral reef organisms undergo a very delicate larval stage that is ideally suited to life on a wild reef but poorly suited to life in captivity. Advances in this area are being made all the time, and there are now a handful of fish and corals that can be reared in captivity. The hard corals do not reproduce very well in captivity; they are, however, being propagated through a process called fragmentation, where fragments that have been broken off existing colonies are cultivated.

Unfortunately, because this is such a new area, organisms cultured in captivity are generally more expensive than their wild caught counterparts. If you decide to set up and maintain a salt water aquarium, you must also bear some of the responsibility, too. Buy and read at least one good reference book. Shop around and find a dependable aquarium store where you'll be able to ask lots of questions and get reliable advice. At least until they become familiar with your set up, the staff should ask you a lot of questions before you buy anything. That way they can help you decide if you need, or should have, a certain piece of equipment or a particular specimen. Only purchase organisms you know you can successfully maintain, which means you'll need to do some research beforehand. Know the organism's diet and habitat requirements, as well as its compatability with other organisms.

Knowing which species to avoid will save money as well as reduce the demand for species that usually die in captivity. Make the commitment to purchase cultured (sometimes called "tank raised") organisms whenever possible.

Suggested Reading

Advances in recent years have made it possible to recreate a small slice of a coral reef in captivity, but it requires time, money, and knowledge. If you feel you are ready and willing to take on the challenge, the next step is to read one or two good reference books. The following is a list of books that thoroughly outline the initial set up and continued maintenance of a marine aquarium.

Bibliography for Aquarium Hobbyists

 

Symbiosis

The ocean is a big place that houses many organisms who are constantly competing with each other for various resources. To improve their chances of survival, many marine organisms have developed close associations with other marine organisms. These associations are known as symbiosis, derived from the Greek term "to live together." There are many different types of symbiotic relationships between many different types of marine organisms. The relationship may involve plants, animals, or both. The association could be so strong that neither organism could live on its own, or the two organisms could just as easily live apart. Generally speaking, three types of symbiotic relationships are recognized:

1) mutualism: both organisms benefit from living together

2) commensalism: one organism benefits, one is unaffected

3) parasitism: one organism benefits, one is harmed However, because we do not always understand the full nature of the relationship, it is sometimes difficult to identify the type of symbiosis. The reason for the symbiotic relationship is often unclear and may involve one or more of the following elements:

  1. Food
  2. Shelter/protection
  3. Cleaning/parasite removal
  4. Transportation Some examples of marine symbiosis include (the first two can be seen in our ecosystems):