Written by Russell McAndrews
Large display aquaria can reproduce, in miniature, an almost natural habitat priceless for behavioral study and education. While some displays are tied to. others to provide for cohesive strategy. Different display and educational tactics are highly variable and largely dependent upon local personnel. Many address the ecological destruction issue directly, but a different tactic recently employed a more positive focus on the interest and value of these animals with a placard containing the barb, “by the way, these fish no longer exist in nature”. Public education is extremely important to the overall mission of tool toward this end. Additionally, these represent a Species Survival Program. Efficient resource management requires that the program make proper use of available large display aquaria. Typically, however, they are under or inefficiently utilized.
II. Defining The Problem
The logistics and parameters of display aquaria can be extremely limiting in a number of ways. This is not the sort of utilitarian tank that can be manipulated easily. Great efforts in pre-planning, coordination and time intensive labor are required to achieve the simplest of tasks. Compounding the physical problems are social/behavioral ones. Although cichlids in general have relatively undemanding physical requirements, they can be completely intolerant of social perturbations, such as those which continuously occur in captive handling. Probably the most lethal example of this would be the introduction (or reintroduction) of an individual into an aquarium with an established hierarchy. While a large display tank tends to be more forgiving of this example due to plentiful space and cover, it is unbending when it comes to the removal of an individual.
Not being able to catch the animals at will or, in some cases, ever again is no small handicap. This particular problem is simple yet thoroughly effective, if the tank is too large or the décor too extensive it is not practical to attempt to catch fish even if it is possible.
Display aquaria very typically must be held accountable to many quarters. Institutions, aquarists and their supervisors all have their own particular agendas. This situation is complicated when an endangered species is involved due to with specific requirements, tracking and reporting.
Peculiarities of display aquaria have not lent themselves well to situations where they were productive in multiple roles, i.e., as a display and as a research tool. From the aquarist’s point of view, priorities would be aligned with the perceived function, education through display. While the perspective of the researcher would lead to an entirely different perceived function, and with it new priorities.
The public itself mandates various aspects of the display. It is the public to whom all displays are ultimately accountable. Presentation is paramount for interests as well as aesthetic reasons. Interesting behavior can act as a display tactic on many more levels than bright coloration. Obviously, color is necessary to catch the viewer’s eye but a display of exclusively color is shallow and uninteresting.
III. BENEFICIAL ASPECTS
Problems with display aquaria are many but then so are the benefits. The large volume of water which is so expensive to medicate is also inherently and wonderfully stable both physically and socially. A system of this nature has a gracious amount of room for error or malfunction.
The uniqueness of the situation is hard to grasp but if the viewer were to don a mask and peer beneath the waves they would not see as much. Haplochromines are relatively small fishes which house well in reasonably small tanks which make the prospects for a large display tank excellent for maintaining a large, socially-interactive group or colony. Additionally, different genera will exhibit particular preferences for cover, food or even the depth at which they live. Many of observations made possible by the large display aquaria would not even be possible in the wild due to excessively turbid water. Behavioral affects become more and more intriguing in direct proportion to the amount of room available for interactions such as schooling or pecking.
These are very gregarious species and, given enough space, they will put on quite a show while exhibiting a myriad of predictable patterns. Aggressive Haplochromines exhibit variations on a vertical bar theme while submissive animals show variations on a horizontal theme. Males will dance and flutter to attract a female, spawning will take place at any time of the day, brooding females will exhibit sunken bellies and a distended buccal cavity and fry will peer from crevasses and dense foliage. Since many of these behaviors are predictable, display placards can project depth and education by indicating a couple of the most interesting to the public.
IV. Exhibit Outlay
Endemic ichthyo-fauna and flora, although interesting in its own right, does not make for an exceedingly pleasing display. While the bottom strata and vegetation levels do vary widely, the lake bottom is by a large mud, the shoreline is dense papyrus and vegetation extending along the surface. Occasionally these floats break off to form rafts which are blown around the lake. The undersides of such rafts are such a tangle of roots that they harbor and protect multitudes of small fish. Some of the shoreline is sandy and it is now known that there rocky outcroppings and two different submerged, reef-like structures comprised of; vast assemblages of an oyster-like mollusc, and a wispy, nebula-like microbial mat.
B. Addressing the Problem
One possible solution is the establishment of a species tank. In more definite terms, although a few scavenger species would be allowed, only one species of haplochromine is present. (Two species may be housed together if they are sufficiently distinct.) The formation of such a colony can be extremely useful while at the same time educational. Predictable behavior patterns will resume as the fish adjust. Additionally, through con-specific interaction, several distinct color patterns will exhibit themselves. Depending on the size of the environment, the population density, and the décor, as it pertains to territorial structure, two or more males will become dominant, performing a never ending dance flashing and fluttering intense coloration.
The gene pool created in such a situation is ideal except for the process of tracking of individual fish. Hence, “studbook” fishes cannot be bred in mixed generations as distinct generation is required to provide for calculation of genetic loss. This caveat aside, the larger the colony, the more diversity. The potential for any or all of this genetic material to reproduce itself is excellent. The glitch is, very low numbers of procreation due to self predation. With good cover every spawn will usually be represented. Actually, in this situation, large numbers of fry would be detrimental to the stability of the biomass. Predation is a natural process albeit in this case it is artificially intensified. Mitigation can be accomplished by providing artificially high amounts of cover.