Stocking

/The Conscientious Marine Aquarist

On Livestocking Marine Systems

by Bob Fenner

Selene need SPACE!

"Saltwater systems are no more difficult than fresh to set up and maintain". This may seem a bald-face lie to the marine novice; what with all the gear, variation in livestock, seeming narrow-ness in new bizarre water quality parameters. But I would bet you dollars to donuts that you too, will utter such a statement in the near future.

Let's face it; given that you take your time and are conscientious (a foregone conclusion since you're reading this), the actual "nuts and bolts" of putting a system together and keeping it that way, can be reduced down to a finite number of "cook-book" steps. With one exception. What is this elusive variable in marine success?

The livestock.

Isn't it strange how we forget how difficult it was to learn to tie our shoes? Or, ride a bike; and an auto? Experience seems to make what was hard or impossible commonplace. So it was probably when you tried your hand at freshwater. Most freshwater livestock is much more forgiving; and for several very good reasons.

Compared with marine environments, lakes, ponds and rivers compared are vastly more unstable, and it logically follows that the life in them has a wider range of tolerance and adaptability than that in the seas.

What is more, a whole bunch of freshwater livestock is "man/person-made". Going through successive generations in captivity goes a long way in making aquatic life more "plastic" to the wiles of human captivity. One of my favorite more-than-two- thousand-year-old Chinese wood-prints depicts a goldfish flopping around on a washboard while it's bowl is being scrubbed. Talk about unnatural selection!

Anyhow, I hope my point is made; the real difference between salt and fresh systems is not so much the systems, but their biological inhabitants. There are several profound ways in which this life differs; principally for marine aquarists is the greater degree of "the unknown" with marines. It is harder to tell a "good" specimen from a shaky one with saltwater.

Think about this. In the wild, marine organisms face tremendous predation pressures. To avoid being eaten some are fleet of fin, or camouflaged, color, pattern or mimicry-wise. Many fishes dive into the sand, between rock and coral to escape becoming meals or captives... The last (or close enough to it) thing any of them wants to do is "let on" that something's wrong with them. You don't see many diseased or damaged marines in the wild; they are quickly eaten.

What this boils down to for aquarists is that, it is very hard to tell when you're observing a ready-to-buy or ready-to-say-bye specimen.

For all the above reasons, plus a few more, steps must/should be taken to assure the selection of clean, healthy and "proper" livestock. The first and last qualities are a matter of knowing what you're looking at, trusting your dealer, and chance.

The most controllable variable in the suitable livestock equation is health, "An absence of diseased condition". How are the subjects being taken care of? What are their and your practices regarding dips/baths, other acclimation techniques and quarantine?

Who Needs All This Baloney?

You and I and everyone else who deals in marines, Dear Reader, that's who. Marine salt mix, another set-up, and all the other paraphernalia and time it takes to adequately introduce new livestock is not a big hassle compared with the infection and loss of your livestock. Let me impress this upon you further.

Fact: most marine hobbyists have been "in the life" for less than a year; on average all have been in the salt interest than less than two years. What happened to all those ex-marine aquarist folks? Did they go "disco", turn to roller-blading or darts instead? No, most just plain gave up. For lack of this useful, valid, complete information and practices, they suffered humiliating, "anomalous" losses, got bummed and trashed their systems.

Please don't let this happen to you. Virtually all marine organisms for aquariums are wild-caught, they are all potential and real carriers of infectious and parasitic diseases, treat them as such. I'm not trying to make you paranoid; but it's a crying shame the hobby and trade are such a backwater in the "States" because of the unnecessary loss of life and hobbyist attrition that could be so easily eliminated.

Unlike many freshwater pathogens (disease-causing agents), the eradication of almost all problem infections and infestations in transit through prophylactic acclimation and quarantine virtually assures a disease-free main system.

Of course, just like the advertisements for new autos, I'll have to throw in a few exclusion clauses; ahem, "Offer excludes poor maintenance and feeding, introduction of disease from food, decor... power outages and other "Acts of God"". "See Dealer for details..." oh wait, that's for cars.

Develop and implement your own "standard operating procedures" for dips/baths, acclimation methods and quarantine. These are not only your best means of guarding against disease spread and loss; they're your only real ones. As you'll see when you head into the voodoo which is marine livestock disease and treatment, the old saw, "An ounce of prevention, is worth a pound of cure" is an extreme under-estimate.

Other Considerations:

So you're convinced as to the worth of the preventative measures listed above; there's more. Here we'll briefly discuss other important aspects of introducing livestock. The issues of timing, density, size, sex and order of placement.

Who's On First?

No matter what type or size system you have there is a necessary "breaking in" period in which bacteria and other microbe populations achieve "dynamic equilibrium" (what a great oxymoron), chemical and physical changes slow (the water "ages") and the present livestock, as they are introduced, "settle-in".

This is a time of great joy (for the aquarist) and peril (for them and their livestock). Too much life in a new tank is not a good idea; wastes in the form of ammonia, nitrites might build up to dangerous/toxic levels, over-stressing your stock.

Thus it can be stated that how much, and how quickly organisms are added is an important consideration. Suffice it here to state that at first only a few specimens (maybe one) may be admitted to a newly set-up, stable system; with a vigilant eye on the selection and presentation of each new one as it is added.

Density/Stocking Rates/Carrying Capacity/Size:

Everyone can't agree on any one darned thing it seems. Some folks like Country & Western, other's Bach; why there's even people who enjoy eating lima beans!

Well, actually, there may be an item we can all get behind; the fact that marine system's should be under-crowded. How much is too much? That depends on many factors; the size and shape of the system, filtration, aeration. maintenance, the kind of livestock, it's size, feeding, temperature, and a whole lot more.

As a real good rule of thumb I'll say, oh, five gallons per cubic inch of livestock is about right. I know this is a very general measure, purposely vague, and with a larger-than-most margin for error; but it will do for almost all circumstances. A veritable fifteen pound treatise (not by me) could be written on all the interacting quantities and qualities that might figure into maximum and optimum stocking rates. All this is irrelevant in light of the above guideline, and:

"When in doubt, leave it out" will become your motto for talking yourself out of that "just one more specimen" which may be one too many. The dynamics of quantifying the carrying capacity of a system is not your only concern. Sure, your filter may be able to support a beluga, but what about the behavioral interaction with the rest of your livestock and that "sea canary"? Don't believe the filter system manufacturers and their writing/advertising lackeys; under-crowd and you and your livestock will live happier, longer lives.

Sex and Order of Placement:

We can chat about both of these at once. Some organisms are very touchy about how many of what sex of them are around (I'll have to write this fast, my wife is looking over my shoulder). Also, the sequence of which types, size, sex of livestock placed in the system can be critical. Some useful tips:

Go slow; study up re the life habits, size and dispositions of your intended tankmates before trying them out. Don't trust just one information source, even if it's Your Humble Narrator. I have seen three foot panther groupers (Chromileptis altivelis) in the wild, irrespective of how big your reference work might say they get.

For the species that are "social", make sure and match them numbers and system size-wise. For solitary types, allow a good few weeks between introducing them.

When adding new livestock "Move the decor, leave some outside light on"; sage, well, at least expensive advice that you don't have to learn first-hand. Moving the rock and coral around will diffuse a great deal of territorial aggression, and having some light in the room will help the new-bee to avoid harassment.

Bibliography/Further Reading:

Burgess, Warren E. 1978. The right size fishes. TFH 2/78.

Dow, Steven. 1986. A math model for estimating aquarium capacity. TFH 11/86.

Hovanec, Timothy A. 1995. Carrying capacity. AFM 11/95.

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