Experimental Techniques

A host of marine species can probably be used as live foods. Copepods, for example, and especially their larvae (nauplii ), appear to be important components of the natural diet of marine fish larvae. Copepods and other small crustaceans may form the bulk of the diet for adult drag-onets, such as Synchiropus picturatus. These tiny crustaceans often undergo spontaneous population explosions in mature aquariums established by the methods outlined in this book. When such an explosion occurs, one can harvest a few hundred of the organisms and transfer them to a separate container in an attempt to establish a culture. Supplying them with algae, detritus, and other organic matter removed from the display aquarium should result in a successful copepod "farm." Mass culture of a single copepod species is also possible, using techniques similar to those developed for Brachionus rotifers.

Aquarists living near the seashore, or able to visit the ocean with regularity, should attempt to establish cultures of natural plankton. As with the cultivation of copepods taken from the aquarium, the approach to working with natural plankton can be simple or more refined. Simply collect seaweed or other flotsam from the beach just after the tide recedes — you'll want material that hasn't been exposed too long. Placing this material in a bucket or tank of seawater

272 Natural Reef Aquariums will result in a remarkable culture of marine invertebrates that can be best appreciated only with the aid of a microscope. As well as being a source of live food, this type of plankton farm can be entertaining and instructive if it can be examined periodically under magnification. (A good microscope, like a good pH meter, should be considered an essential tool for a serious marine aquarium hobbyist. Magnification in the range of about 10X to 100X is most useful. The instrument need not be expensive. Used microscopes can sometimes be found in pawn shops or in surplus-property auctions held by colleges. If the lenses are not scratched, a used scope can be a real bargain.)

A sprig of seaweed the size of the parsley garnish on your dinner entrée is sufficient to establish a marine protozoan culture in a quart of seawater. Simply fill a jar with water directly from the ocean, drop in the seaweed, or perhaps a chunk of wood encrusted with small invertebrates, and place the jar in indirect sunlight. Aeration will result in a different sort of community of microorganisms than would be the case without it, but is not necessary for producing food organisms. Even the death and decay of the seaweed or other life forms will not spell catastrophe, because this will, in turn, feed another cycle of growth for other kinds of plankton. Examination of the container every day will reveal a changing pattern of life. You might even choose to remove an especially useful species to its own tank or jar for mass cultivation.

O ne need not collect the original starter material from the Tropics in order to use the organisms as food for tropical invertebrates. I know of at least one case in which such a plankton farm from the Chesapeake Bay was used successfully to rear the Mandarinfish, Synchiropus splendidus.2 For feeding a typical invertebrate aquarium, I recommend using a 10-gallon tank for the farm, although one can have

2 Julian Sprung, personal communication dozens of plankton aquariums in quart jars on a windowsill as well.

A more refined, albeit very expensive, approach to the use of plankton in marine aquariums is to go out to sea in a boat periodically and tow a plankton net through the currents. The resulting catch is returned to a holding tank or tanks on shore and subsequently used for feeding. While elegant (some hobbyists even time the plankton tow to match natural spawning cycles of fish and invertebrates in order to duplicate the natural conditions), this option is clearly available only to the dedicated marine enthusiast who lives near a coast.

Supplementation

Marine fishes and invertebrates require certain elements in order to grow and reproduce. These include food components, such as proteins, fats, and carbohydrates, as well as calcium, strontium, iodine, and other minerals. Trace elements and vitamins may be required by some species, although little is known about the food requirements of the majority of marine organisms. Experience has taught reef aquarium enthusiasts that supplementation of some important elements enhances the growth rate of coralline algae, corals, tridacnids, and other specimens. CALCIUM. Natural seawater contains approximately 412 mg/L of calcium. This chemical element is required by all forms of life, but is especially important to organisms that secrete a calcium carbonate skeleton, or that have calcium carbonate as a component of the exoskeleton. These include certain species of macroalgae, corals, mollusks, tube-worms, crustaceans, and echinoderms that extract calcium from the water. (Calcium chemistry in the aquarium is discussed in Chapter Five.)

STRONTIUM. Strontium is present in natural seawater at a concentration of 7.9 mg/L. A test kit for strontium is

Chapter Twelve 273

STRONTIUM CHlOf

20% SOLUTION

CAUTKW , 4WAV FROM WK?

Oifttarttt 1ÊE1.1I

Aquarium and Fish Care Tactics

Aquarium and Fish Care Tactics

Who Else Wants To Learn The Secret Tactics For Setting Up And Maintaining A Solid Aquarium Set At Home And Get The Most Exciting Information About Aquarium Fish Care In A Decade. You're about to discover the most comprehensive report on aquarium and fish care you will ever read on the internet in the next five minutes.

Get My Free Ebook


Post a comment