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The Temperate Reef Tank - Part Two

A variety of invertebrates and fish are suitable inhabitants.

By David Wrobel

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Just as with tropical reef systems, it is possible to create a stunning temperate reef masterpiece solely with a variety on invertebrates. Fish-dominated displays can also benefit from the addition of invertebrates. There are certainly many invertebrate species to choose from. Kelp forests and intertidal zones are inhabited by an astounding variety of life forms. However, only a small number are truly suitable for the aquarium.

Most kelp forest fishes will survive quite well in an aquarium environment (as long as they are not too large), but invertebrates are far more variable as to how well they will adapt to a closed system. Only those species with a reasonable chance of survival should be attempted. Adding a random mixture of different species into your system without regard to their behavior patterns or hardiness will probably result in a nasty mess. You should never expect to duplicate the amazing complexity of a temperate rocky reef ecosystem in your aquarium.

The following is a brief list of some of the most suitable species for a temperate aquarium. You can try including others, but they must be kept under careful observation. That way, if there are problems, you will notice them before there is a major disaster in the tank.

Anthozoans
A wide variety of these beautiful relatives of the jellyfish are common inhabitants of kelp forests and tide pools. Sinuous tentacles studded with ensnaring and stinging nematocysts effectively capture passing prey. Most species are quite hardy and colorful, and they make excellent additions during the break-in phase of a new tank.

Anemones and corals are familiar members of this ecologically important group. Most thrive only when sufficient water motion is present. Many anemones will actually glide methodically about the tank until a site with adequate motion is found. Anthozoans should never be situated so that the tentacles of two individuals or colonies come into contact. Serious damage to both can result.

Large anemones may be fed about once a week with a piece of squid, shrimp or fish placed on the tentacles. Smaller colonial forms, such as cup corals and strawberry anemones (Corynactis californica), which are actually corallimorphs related to the so-called mushroom anemones of tropical reefs, will require smaller fare — brine shrimp or chopped krill. Turkey basters are excellent for squirting food directly among the individuals within a colony. White-plumed anemones (Metridium senile) also require small bits of food. Anemones and cup corals can be coaxed to spread open their tentacles by squirting squid or shrimp juice in their vicinity. Feeding should be attempted only after complete flowering of the tentacles.

Strawberry anemones can add a truly spectacular dimension to your display. Large patches of rock walls in kelp forests are often blanketed like vibrant jeweled tapestries, with various shades of red, pink and violet distinguishing the colonial groups. Within the aquarium, they can be induced to slowly cover a rock through repeated divisions (provided feeding is sufficient), forming a sparkling component of the display. The addition of a couple of larger rose or white-spotted anemones (Tealia species) will enhance this display even more. Cup coral colonies contribute brilliant dashes of bright orange.

The giant green and the aggregating anemones (Anthopleura species) are two of the few temperate invertebrates requiring light because they contain symbiotic algae that aid in providing food. Insufficient lighting will result in a loss of the attractive green coloration. The relationship between the anemone and algae is not absolutely essential as it is in tropical corals, however, and a blanched anemone will continue to survive if fed regularly.

Tube anemones (cerianthids) are interesting additions to the temperate aquarium. The unattractive, slimy brown tube should be buried in the substrate or nestled in crevices among the rockwork, leaving the sinuous tentacles and a portion of the tube exposed. They are extremely hardy. However, beware that there is also potential danger to other invertebrates because the long tentacles of the tube anemone can inflict damage if contacted.

White-plume anemones are a more mysterious addition. Although quite attractive, they rarely display their full splendor. If you attempt to keep these easily annoyed anemones, do not be surprised if they remain continuously closed or seem to move endlessly about the tank.

Echinoderms
The spiny-skinned echinoderms include the familiar sea stars and other less well known, often bizarre invertebrates. Most are plodding, persistent predators or grazers, using several unique methods for procuring food.

Many echinoderms are seemingly harmless, placid creatures. Sea stars, however, include a number of efficient predators that ravage beds of sessile (sedentary) invertebrates. Using stomachs that can be turned inside out, they dispatch their hapless prey in a gruesome manner. Care must be taken when selecting sea stars for a temperate aquarium because certain other sessile invertebrates may be imperiled. Admittedly, the bright flashy colors of many sea stars are an incentive to overlook their predatory habits.

Bat stars (Patiria miniata) are among the most plentiful and colorful of the kelp forest and intertidal sea stars. Many individuals are adorned with splendid kaleidoscopes of color patterns, creating mobile patches of red, orange, violet and beige in the tank. They are not quite as ravenous as some of the other sea stars, but do make excellent scavengers of excess food. Often they seem to beg for food by exposing their undersides at the surface of the water. Bat stars should be provided with a bit of fish or shellfish about once a week.

Ochre and giant-spined sea stars (Pisaster species) present more of a threat to tank inhabitants, particularly gastropods (snails). Smaller individuals should be selected and watched closely for any undesirable activity. Rainbow stars (Orthasterias koehleri), although quite beautiful, are even more apt to cause trouble — no snail can rest comfortably when one of these is in the tank.

Despite their name, the dining habits of blood stars (Henricia species) are far less objectionable than their more predatory relatives. They subsist primarily on small particles — adhering to mucous on the upper surface of their bodies — that are then brought to the mouth.

At the other end of the spectrum are the innocent-sounding sunflower stars (Pyncnopodia helianthoides). These spry (for a sea star) monsters should never set any of their more than 20 arms in your aquarium. In addition to their destructive behavior, they may also release toxins into the water.

Related to the sea stars are the aptly named brittle stars. Brittle stars are nocturnal scavengers and usually hide under rocks with only the tips of the spiny arms exposed.

Urchins are another group of echinoderms with far more secretive habits than their conspicuous sea star relatives. Most tend to be active at night, when they come out in full force in search of seaweeds and other materials to feed upon. Although their nocturnal nature is usually retained in the aquarium, the algae grazing behavior of urchins can be of enormous benefit in controlling fouling algae. Several red or purple urchins (Strongylocentrotus species) will go a long way toward reducing pesky filamentous growths. They may have a tendency to overdo it, however, and large individuals in particular may take a fancy for display seaweeds.

The bizarre sea cucumbers have a few kelp forest representatives that make nice additions to the aquarium. Small warty and California sea cucumbers (Parastichopus species) are handy scavengers, endlessly sifting through the gravel and rockwork while picking up organic particles with sticky oral tentacles. Although rarely seen, they perform a useful function.

Crustaceans
The often cantankerous crabs are members of this diverse, wide-ranging group of hard-bodied creatures. Many contribute welcome activity to the display tank. In general, small individuals should be favored because they are far less likely to inflict major damage to other tank inhabitants. All are excellent scavengers, picking up loose bits of food that would otherwise decay.

Most aquarists are familiar with tropical hermit crabs, and temperate habitats are no less endowed with their own interesting representatives. Several species are extremely common in tidepools and subtidal habitats. Their antics can be quite comical while scampering about with their weighty shell homes. Many serve a useful function by consuming undesirable algae growths.

Masking, mimicking and sharp~nose crabs are excellent additions to the aquarium. Masking crabs (Loxor~hynchus crispatus), however, can grow quite large and troublesome. Their habit of decorating the upper surface of their shell can result in the unfortunate shredding of seaweeds and sessile invertebrates. Kelp crabs (Puqettia species) are another attractive species with destructive habits that can be controlled only by selecting individuals that are smaller. One of the more desirable crustaceans for the temperate display is the coonstripe shrimp (Pandalus danae). These dazzling shrimp are adorned with electric blue and red patches. Often common in areas with abundant rock rubble and crevices, they will seek similar protective hideouts within the aquarium.

Mollusks
This incredibly diverse group runs the gamut from plodding snails to nimble, highly intelligent octopi. Most mollusks suitable for the aquarium are grouped within the large gastropod class, which includes snails, limpets and nudibranchs. Several types of temperate snails are particularly effective as the first line of attack against the ravages of fouling algae.

No temperate aquarium should lack the services of the turban snails, a group of unparalleled algae grazers. The red turban (Astraea qibberosa), in particular, is masterful in its efforts to rid rocks of persistent filamentous and brown diatom growths. Without these tireless workers, a lush carpet of choking filamentous growth could threaten to take over. Smaller Tegula snails are extremely common in tide pools and function in a similar manner. Juvenile abalone will also scour the rocks, but make sure you acquire them legally (size limits apply in most areas).

Most temperate snails are rather drab, but nevertheless add to the completeness of your miniature ecosystem. Not all snails are algae grazers. Many, in fact, are scavengers or even predators on other invertebrates. Omnivorous top shell snails (Calliostoma species) include several species that seem to ignore the color restraints on most gastropods. The jeweled top snail, in particular, is dressed with a gaudy gold/purple shell that adds a pleasing sparkle to any display.

Nudibranchs are equally resplendent, but most species should be avoided unless their specialized food requirements can be met. One colorful and common species that may be tried, Hermissenda crassicornis, is more omnivorous and should be able to find food in a tank with invertebrate-covered rocks.

Chitons are herbivorous mollusks that resemble gastropods but are actually grouped in another class. Two of the best for the temperate aquarium are the lined and giant chitons. Lined chitons (Tonicella lineata) are colorful grazers on pink encrusting coralline algae. Only small giant chitons (Cryptochiton stelleri) of 1 to 3 inches in length should be selected. This species can exceed 12 inches in length and must be watched closely for a tendency to consume display seaweeds.

Fishes
Temperate reefs certainly lack the colorful denizens of the tropics, but this still leaves much of interest. Endowed with their own beauty, and possessing endless variations in behavior and body shape, the temperate fishes are every bit as desirable as their more gaudy relatives. They are actually not totally devoid of bold coloration, and, in fact, many species are painted with rather attractive colors and patterns.

The list presented here includes only those species that do well under general conditions. Species such as pipefish and tubesnouts have more specific requirements and should be housed in aquariums by themselves. Size differentials must also be taken into account, because just about any fish will eat smaller individuals, even if eating fish is not a normal behavior for the species. Natural history guides should be consulted for range and habitat information for each type. This list is by no means complete, and other species may be tried with varying degrees of success.

Rockfish
Among the more common groups of Pacific coast fishes are the rockfish (genus Sebastes). Despite their name, rockfish are found in a wide range of areas and habitats, from kelp forests to the depths of subsea canyons. Many of the more than 60 species are suitable for the aquarium. While some are bland and dull, others are adorned with exquisite color patterns. As members of the notorious lionfish family (Scorpaenidae), all rockfish have dorsal spines armed with irritating toxins. Although not nearly as painful as their lionfish and scorpionfish relatives, the spines certainly deserve some respect.

Adult rockfish may exceed 2 feet in length and are obviously unsuitable for the typical home aquarium. In addition, many become territorial and highly belligerent toward their kin. The more peaceful juveniles are obviously a far better choice. Rockfish are blessed with great hardiness and will eat just about anything you provide, including smaller fish! Within the aquarium, most tend to be a bit sluggish, interspersed by periods of high activity — particularly at feeding time.

Some of the more common species include blue, copper, kelp, yellowtail, black-and-yellow, gopher, half-banded, olive, flag and black rockfish. Among the most colorful are the attractive vermilion, canary, rosy and china rockfish, but they are usually more difficult to come by. Most grow quite rapidly, so it is in your best interests to feed at moderate to low levels.

Sculpins
Although lacking grace and elegance, the wide-ranging sculpins are characterized by incredible patterns of colors and textures. As bottom dwellers, they lack the streamlined shape of sleek open water species. Many are embellished with flaps of skin that render them nearly invisible while calmly resting among patches of seaweeds. Sculpins are bad news for passersby who stumble near the waiting mouths of these ferocious sit-and-wait predators.

Many sculpins are common residents of tide pools and subtidal habitats, and they make excellent and quite hardy aquarium inhabitants. While not always adding much to the activity level of your aquarium, sculpins will nevertheless significantly boost the aesthetic value of the display.

One of the more common sculpins is the cabezon (Scorpaenichthys marmoratus), a monstrous member of the family that should be treated with respect. The placid countenance belies a treacherous habit of pouncing on just about anything that moves. Only small individuals, which are often quite colorful, should be attempted.

A less menacing prospect is the diminutive snubnose sculpin (Orthonopias triacis). Those boldly colored beauties have relatively small mouths and are limited to tiny bottom-dwelling prey. Somewhat more threatening are the woolly (Clinocottus analis) and coralline (Artedius corallinus) sculpins, which cannot be trusted with smaller fish.

Two of the oddest temperate fish are grunt and sailfin sculpins. Bizarre grunt sculpins (Rhamphocottus richardsoni) would hardly win any beauty contests, but add a great deal of comic relief while scooting about the bottom on their pectoral fins. A unique undulating dorsal fin distinguishes the sailfin sculpin (Nautichthys oculofasciatus), which seems to use the waving appendage to mimic seaweeds.

Surfperch
An elusive goal of many marine aquarists is to successfully breed their specimens. The surfperch family provides an opportunity to fulfill this dream with relative ease. All surfperch are livebearers, producing miniature copies of the adults — bypassing the tiny larval stage of most fishes.

About 20 species of surfperch inhabit United States coastal waters. All swim ceaselessly — a source of frustration to collectors — but they provide a welcome boost of activity to an aquarium. Surfperch tend to be browsers and will pick at invertebrates and seaweeds in the tank. They are rarely a threat to other fish unless the size disparity is large. At feeding time, most surfperch will eagerly devour anything within their size range, although the more reticent juveniles may shy away if there is too much activity.

Small species, such as shiner (Cymatogaster agqregata), kelp (Brachyistius frenatus) and reef (Micrometrus aurora) surfperch, may be kept as adults and are best for breeding purposes. They present a definite possibility for observing courting and breeding behavior.

Colorful black (Embiotoca jacksoni), striped (E. lateralis) and rainbow (Hypsurus caryi) surfperch add flashes of color, while attractive silvery coloration is the calling card of barred (Amphistichus argenteus), pile (Damalichthys vacca) and walleye (Hyperprosopon argenteum) surfperch. With the exception of the cantankerous black surfperch, the juveniles of all these species do best when kept in groups of three or more.

Additional Deepwater Species
The Clinidae family includes both beauties and beasts. Shy kelpfish (Gibbonsia species) are one of the temperate fishes that can compete admirably with the coloration of tropical species. Seemingly emblazoned by the work of a deranged artist, these hardy fish — with their cryptic coloration — are a welcome addition to a display tank.

Fringeheads (Neoclinus species), although in the same family, are at the opposite end of the beauty spectrum. These curious beasts usually occupy crevices and other small openings with only a comical face exposed. The smallish yellowfin fringehead is excellent for cramped quarters, while the onespot fringehead is more suitable for larger aquariums. Males have a tendency to become very intolerant of each other.

Gobies are a familiar tropical family, with several interesting representatives in temperate waters. The brilliant, albeit small, bluebanded goby (Lythrypnus dalli) is a must addition to the temperate display. Larger fish, however, may relish their small size. The extremely common blackeye goby (Coryphopterus nicholsii) is also an excellent addition. Males (distinguished by obvious black pelvic fins) may do battle within aquarium confines and should not be paired in small tanks.

Within the hexagrammid family, painted greenlings (Oxylebius pictus), also known as convict fish, are a must for the temperate aquarium. They are extremely common and hardy, and are painted with vibrant reds and browns. These greenlings are relatively active for bottom-dwellers.

The prickleback family includes the bizarre eel-like monkeyface prickleback (Cebidichthys violaceus). Growing up to several feet long, only juveniles of these secretive, algae-eating fish should be selected. If the tank contains a sand substrate, several types of flatfish may also prosper, such as juvenile turbots and sanddabs.

Several deepwater sharks can be suitable for temperate aquariums. As newborns or juveniles, both horn sharks (Heterodontus francisci) and swell sharks (Cephaloscyllium ventriosum) usually do well in a tank devoid of anemones. They gobble down bits of squid, prawn or clam, but usually only after a piece is placed by their mouth.

Additional Open Water Species
Fish that spend their time actively swimming about the aquarium help to balance the display. In addition to rockfish and surfperch, several other common species can make a contribution.

The tropical damselfishes have a couple of temperate representatives, the blacksmith and garibaldi. The pugnacious blacksmith (Chromis punctipinnis) occurs in large schools in the kelp forest and are best kept as more peaceful juveniles. Many marine hobbyists have seen photos of the bright orange garibaldi (Hypsypops rubicundus), which can make a sparkling addition if you can acquire a juvenile.

The sea chub family includes several attractive Southern California species. Even as juveniles, halfmoon (Medialuna californiensis), zebra perch (Hermosilla azurea) and opaleye (Girella niqricans) can be extremely nasty and may terrorize all other fish in the display.

The familiar wrasse family includes the senorita (Oxyiulis californica), a common schooling species of the kelp forest. These frenetically active beauties are difficult to capture but well worth the effort. Their apparent disappearance from the aquarium should not be a cause for alarm, as they tend to bury themselves in sand and gravel.

Seaweeds
A trip to any tidepool or kelp forest will convincingly demonstrate the importance of seaweeds in temperate marine habitats. Hundreds of species carpet rocks and walls, often to the exclusion of invertebrates vying for precious space. Within the aquarium they can transform a bland display into one worthy of rapt attention. Subtidal red algae are the best for a closed system, with many attractive species available that will survive for varying periods of time in an aquarium.

The slow-growing, erect, encrusting coralline red algae are particularly attractive and suitable for aquarium life. Encrusting corallines form the beautiful pink patches coating rocks and will survive quite well under aquarium conditions. Other species of red algae may be tried and often do quite well, but should be removed when undergoing rapid loss of color or deterioration. Brown algae are better adapted for the rigors of tidepool life and may cause problems if they begin decaying in the quiet environment of an aquarium.

All seaweeds should be collected with the holdfast intact. This attachment structure can be wedged into crevices or even glued with cyanoacrylic adhesives onto the smooth surfaces of rocks (both surfaces must be dried with a paper towel before attempting to apply the glue).

In an aquarium with insufficient water motion, seaweeds may become fouled by filamentous algae and detritus. Once a week, and preferably on a more frequent basis, you should vigorously blow water with a turkey baster over all the seaweeds. They are, after all, adapted for environments with a great deal of surge and turbulence.

In summary, discard any naive notions you may have had regarding coldwater aquariums and cast aside the belief that temperate reefs are populated only by a small number of bland and dull creatures. One look at a well-maintained temperate display will open a whole new world of possibilities. Good luck!

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