The Biome Approach: A Tale Of Two Reefs

By: Greg Collinske

It seems like whenever we consider starting a new reef aquarium, we always come back to thoughts about the two very large reef exhibits in Denver’s Downtown Aquarium.  We believe each of these display a stunning and bold illustration of what can be achieved in aquariums that aim to mimic an area as closely to true nature as possible.

These two reefs are both equally beautiful examples of deliberate choices in both livestock and equipment used to recreate a particular section of a reef biome. The possibilities in creating these biotopes are endless, and these are just two large instances that could easily be scaled down almost indefinitely to accommodate any taste or needs.

The differences in the amount of water flow and brightness of the lighting are both fairly apparent in the two displays. We noticed the color and intensity of the illumination are again quite opposite of each other when we take a look from above both exhibits.

We love the fact that the stocking of both fishes and corals in each of these two reefs couldn’t be more different; one is a predatory fish reef focused on soft corals, LPS corals, clams and macro algae. The other, is a high energy surging SPS coral reef complete with an extensive list of anthias, tang, angelfish and butterflyfish species playing in the currents.

Life in the Land of Giants

The predator reef fishes are larger species of snappers, groupers, rabbitfish, eels and tangs. The stocking density reflects this with just a few fish in the large environment. The corals, clams, and algae benefit from the higher nutrients provided by their large swimming tankmates, and they thrive in the lower lighting conditions.   

The rock structure is designed to allow for large nooks for the snappers and groupers to disappear from view for a few moments, as well as for several eel caves.  This more open design allows for passive flow to be effective like a gentle wave, and an almost glass like surface at times imitating the calm backside of a reef crest. 

Life at the Top of the Reef

The dynamism of the SPS aquarium is breathtakingly beautiful with its large colonies of corals and an extensive number of fishes teeming throughout the perfectly filtered water column. The relaxing blue glow and shimmer of actinic lighting adds a calming background effect against the extreme fluorescence of colors shown by both the fishes and the corals.

Space on this reef seems to be very hard to find for both the fishes and the corals, with small battles always erupting; corals showing telltale marks where another coral had intruded and fishes territorially chasing each other. All of this life is successful in this chaotic, yet low nutrient environment, and this is achieved primarily through engineered intense lighting, fast water flow, and effective protein skimming.

Take Your Pick

The amount of fishes in each of these displays are again completely contradictory, however, both aquariums’ fishes are fascinating and balance amazingly with the corals around them. We still struggle sometimes to choose between: The size and color of the large predators swimming slowly around big mature coral heads, or the schools of anthias and tangs lining up to be happily cleaned by a skunk cleaner shrimp on a nearby coral.

There are many facets to maintaining an effective reef, this article concentrated on the mimicking of illumination, water flow, and stocking density considerations for biome type aquariums. These topics can help to start the process of defining what type of aquarium setting is ultimately desired by any ambitious reef aquarist.