AHABS... Issue Ten

It Is A Competition; Turf Wars In Reef Tanks


Ronald L. Shimek, Ph. D.


Reef aquarists and, I suppose, the public at large, often tend to live in a world that is only slightly tangent to reality. Of course, authors such as myself are ALWAYS on top of things and are all knowing… J (And, if you believe this last statement, I know of several bridges for sale, just send me some money, and I will be sure to give the most pertinent information possible about them.) Nevertheless, regarding coral reef biology this paragraph's topic sentence is horribly true. As an example, one often sees in reef-aquarium literature and forums comments something like the following: “Coral reefs, islands of harmonious life in an otherwise empty oceanic void, are full of animals living and working together in a benign and cooperative ecosystem.” The conception of reefs are somehow benign environments is pervasive in the reef hobby and amongst the general populace and I think it is responsible for a lot of the popularity of coral reef SCUBA diving trips. In many peoples' minds, the reefs are so beautiful that they must be a peaceable world, a world so different from reality that it is a good place to escape to.

Figure 1. Although the scene shown here looks peaceful, nothing could be further from the truth. The array of organisms to the right of the Acropora is a veritable battlefield of potential competitors..

Information Evaluation


Ronald L. Shimek, Ph. D.

“ Wouldn ' t it be wonderful if the response to the next anecdote ” being “ passed around the campfire ” was, How do you know that's true ? ' ”

A Paraphrase Of A Statement By Eric Borneman


Many of the topics that I have written or spoken about over the last several years have a major theme: “The need for hobbyists not only to reason clearly and critically, but to evaluate their information sources in the same manner.” Clear reasoning and critical thinking are exceptionally important in our hobby. Probably the most vital component of animal husbandry is the ability to “think” a problem through, and then be able to rank and subsequently act upon the resulting options. I have been writing my articles in this magazine with the goal of providing assistance for those people who realize that a lot of the popular reef aquarium information is at its best fallacious and at its worst dangerous to reef animals and, by extension, to reefs themselves.

Over the last decade or so, I have written a great many articles wherein the main thrust has been a discussion of the properties of the various animal groups found in marine reef aquaria. Additionally, as in the main article in this issue of AHABS, I have elaborated a bit on the themes of the ecological relationships found amongst reef animals, or discussed some aspects of water chemistry that I think are important. With regard to the various animal groups, I have provided lists of the major characteristics of each type of animal I have discussed. My expectation has been that, with a bit of reason and thought, most aquarists should be able to utilize all of this information either to manage the care of desirable organisms or to eliminate undesirable ones. However, such an outcome is only possible when the aquarists are thinking clearly with reasonable and valid information at their disposal. Unfortunately, in this hobby, valid and reasonable data are exceptionally hard to acquire. And unfortunately, the ability for thinking clearly doesn't seem to be a prerequisite for establishing a reef aquarium . What information is available is often hidden by obfuscation or comes from, at best, questionable sources; primarily magazines and books published by people whose main qualifications for producing these tomes seems to be the knowledge of the address of the nearest photocopy center. Not surprisingly, this burgeoning volume of dubious and false information severely impacts the care of all of our animals...

A Few Little Things


 Ronald L. Shimek, Ph. D.

 Vicious Viscosity

 Many of the smaller invertebrate or invertebrate-like organisms in reef aquaria are well known to the aquarists maintaining those aquaria. Often the biological attributes or behaviors of these small organisms are observed, and the aquarist may reach some conclusion about those creatures based on what they have seen, and assume the behavior is simply characteristic of the organism in question. However, many of the factors influencing these organisms are strictly a consequence of their small size and are not really dependent upon the creature at all; rather they are a reflection of how physical laws result in small organisms being much differently affected by common physical properties than are larger creatures. Some of these changes due to the size scale of the organisms involved are not necessarily inherently obvious and many of them may be difficult for aquarists to comprehend.

“Strange” things happen in water when organisms are either very small or possess very little mass. As I have mentioned many times, as aquarists we tend to interpret the world from our own perspective. There is absolutely nothing wrong with this, but in doing so, we must continually perform “reality checks” and realize that our perspective may not either be relevant or it may not always provide an appropriate explanation for events we watch, particularly if those events are in aquaria, and particularly if those events involve very small animals.

 For the purpose of this article, I will focus on a few of the potential misinterpretations that are due to size. Humans are among the largest animals on Earth; surely there are larger animals, but just as certainly, well more than 99.99% of all animals or animal-like organisms are smaller. And many of them are VERY much smaller. This size difference does have some profound consequences. Down to about the size of small aquarium fishes or, perhaps, small bristle worms most of the things that we take for granted about the world still work in ways that are familiar. But for very small organisms, well… it is like going through the looking glass after Alice : things can become very bizarre.

 With regard to aquarium organisms, often what appears to be strange is a result of the organisms' living in water. Water, like air, is a fluid medium. The properties of fluids relative to organisms living in them depend upon the molecular properties of fluid's constituents, as well as the sizes and shapes of the organisms. We humans are used to air as one fluid medium with certain properties and to water with another altogether different set of properties. Yet, there are similarities between these media, and we can move through both of them relatively easily. This ease of movement depends largely on our mass. Once we start to move, our mass ensures that we build up momentum, or inertia, which allows us to move though the medium fairly easily...


Ron Shimek