REEF TECTONICS

Brown Blotch Snail (Babylonia spp.)

2011-12-26T10:33:00.001-08:00

There are a number of snails that are employed to help turn the upper layers of the sand bed and to scavenge on food items that come to rest on the aquarium bottom. Most of these are small, relatively bland-looking snails. For example, the members of the genus Nassarius are probably the most often utilized in this role. There common name, mud snails, attests not only to their habitat preferences but also their not so sexy appearance! But there is a genus of gastropods that is not only effective at clean-up duties, but also are very attractive. These are the snails in the genus Babylonia (family Babyloniidae), two or more of which show-up in the aquarium trade on occasion (including Babylonia zeylanica and B. formosae). These snails sport butterscotch colored blotches on a white to yellowish-cream background. They reach an appreciable size for a snail (around 2.5 inches) and are harvested for human consumption in some parts of Asia.

The Babylonia spp. are excellent scavengers. They spend most of the day living under the sand. Usually, all you see of them at this time is their elongated “trunk” (proboscis) sticking from the substrate, that is until an olfactory stimulant is added to the tank (e.g., fish food). Then they erupt from the sand and begin to search for the source of the smell. They can move at a pretty good clip and will consume any meaty food that makes it to the sand bed.

While they are attractive, effective scavengers, the Babylonia spp. are rumored to have a “dark side.” They have been reported to feed on smaller snails and have even been implicated on attacks on tridacnid clams. I have kept individuals with numerous Nassarius snails and while they may have picked off an occasional gastropod neighbor, they certainly didn’t decimate my population of smaller snails over the years that I had them. I have never kept this animal with bivalves, but would avoid doing so or do so with caution. While they may occasionally knock off other mollusks, they are not close to being as lethal as the whelks (family Buccinidae) that are sometimes available.

© Scott W. Michael

GOIN TUBING! Keeping Tube Worms (Families Sabellidae and Serpulidae)

2011-12-26T10:31:00.000-08:00

The beautiful Coco Worm (Protula magnifica) is a difficult animal to keep long-term.

Tube worms are beautiful, fascinating members of the class Polychaeta. They are also the most popular polychaetes available to aquarists. Larger species are intentionally purchased and added to the reef tank because of their elegant form and or their lovely colors, while smaller species often come in with live corals (i.e., living on the rocky bases that the corals are growing on). Unfortunately, the larger species often don’t fare as well as their much-malign brethren, the bristle or fire worms.

Unlike the fire worms (and many other species in this group), the tube worms are sedentary. They form a tube in which the body is hidden and have a spiral crown that projects from the tube. The crown, which is comprised of feather-like structures called radioles, is used for suspension feeding and for respiration. While they have cilia on the feather-like structures to direct food down each appendage into the mouth, they also depend on water currents to bring them tiny food particles. When the worm “feels” threatened, the radioles are rapidly rolled up and pulled into the tube. Even though they can withdraw the crown very rapidly, the radioles are sometimes nipped off by fish species before they can be retracted. The body tube, which is created by the worm, is comprised of sand grains and mucous in many sabellids (e.g., feather duster worms [e.g., Sabellastarte]), or is calcareous in the serpulid worms (e.g., Christmas tree worms [Spirobranchus], coco worms [Protula]).

The Christmas tree worms (Spirobranchus sp.) are beautiful coral obligates that may help coral colonies survive attacks from crown-of-thorn sea stars.

“Oh Christmas Tree”

The Christmas tree worms (Spirobranchus spp.) have an operculum that plugs the end of the tube when the worm withdraws into it. Their larvae settle out of the plankton (larval lifespan is about 12 days) on to a preferred host coral and begin creating their tube. The type of coral they live will impact their overall size and hence their reproductive success (i.e., larger worms, produce more gametes), so they are selective about who they settle on! In some cases, there will only be one or a few of these worms per coral colony, but in some cases, a coral head may be covered with Spirobranchus. Densities of up to 414 worms per 10 square feet have been reported on some heavily infested colonies. Not only do the calcareous tubes these worms produce provide shelter for the individual polychaetes, the empty serpulid tubes serve as a home for tube blennies (family Chaenopsidae) and the coral hermit crab (Paguritta spp.). Some members of the genus Spirobranchus are simultaneous hermaphrodites (they have both functional male and female sex organs), while others are gonochoristic (are either male or female). While many simultaneous hermaphrodites do not engage in sex fertilization, these worms can and do and the resulting embryos are viable.

One more quick note about Christmas tree worm taxonomy. There are many different species in this genus, although most are labeled in the popular literature as Spirobranchus giganteus. They are difficult for aquarists to tell apart without killing the animal and examining the hidden parts as well as the operculum.

The fan or feather duster worm is a demanding animal that will have to be fed suspended foods frequently. Avoid purchasing individuals that have lost their crowns.

Tube Worm Husbandry

If you purchase a larger sabellid feather duster worm, the first thing you need to consider is placement in the aquarium. I would recommend drilling a hole in a piece of live rock (with a masonry drill bit) and placing the sedimentary or soft tube into the hole. You could also place the tube in preexisting holes or crack in the hard substrate. While they need current to push food items past their radioles, a strong, direct water jet can damage them and/or prevent them from unfurling the feeding crown. When selecting a feather duster, never purchase an individual that has crawled completely or even partially out of its tube. These individuals are not likely to live long.

The key to keeping these animals healthy is feeding. If you are not willing to frequently feed your tube worms (of any species), you should avoid purchasing these animals as they are going to slowly starve to death in your aquarium. The larger species of feather duster and Coco worms feed on phytoplankton, small zooplankton (including ciliates, rotifers and invertebrate larvae), and suspended organic detritus. The smaller species, like the Christmas tree worms, ingest bacterial floc (i.e., a chemical precipitate) and minute particles of suspended organic detritus. The best way to provide nutrients in the aquarium is to feed phytoplankton, small zooplankton, and liquid foods for suspension feeders (larger worms need larger food items). Smaller species of feather duster worms (those that often come in on live rock) tend to do better in home aquariums than larger species, which tend to have higher metabolic needs and thus need to be fed frequently. When target feeding, direct the food to the side and slightly below the feeding crown, do not direct it into the center of the feeding crown.

These worms are sometimes fed on by shrimps and crabs. Sea urchins have been implicated in chewing through the sedimentary tubes of Sabellids. If stressed, the tube worms will shed the feeding tentacles, which will typically regrow in several weeks’ time. They may lose their feeding tentacles if underfed, in which case the regenerated tentacles will be smaller. These worms are good plankton-feeding indicator species because they are so effective at suspension feeding - if your feather dusters are starving, then any other animals in the tank that rely on this feeding strategy will be in even worse shape.

While the beautiful Christmas tree worms which are offered along with their coral associate (often Porites spp.), may live a long life in the wild (20 years or more), they are typically short-lived in captivity because they tend not to get enough to eat. One common misconceptions it that Christmas tree worms rely on their coral host for food and if the coral dies, the worms are soon to follow. While they are an obligate stony coral associate (some also live on the hydrozoan, Millepora – i.e., fire coral), they will continue to live even if the coral colony dies. So do the worms benefit the coral at all? Recent studies have shown that the worms may actually protect colonies of Porites coral from being totally consumed by crown-of-thorns sea stars (Acanthaster planci). These sea stars are infamous for occasionally appearing in large numbers in the Indo-Pacific and wiping out swaths of coral reef. It turns out, that portions of Porites colonies that harbor Spirobranchus are apparently protected by the presence of these worms and thus can regrow. The tube feet and/or inverted stomach of the crown-of-thorns is thought to be irritated by the worms, which results in an area of live coral tissue being left beneath the branchial crown of the Christmas tree worm (this section is usually 3 to 5 cm in diameter). This ensures the survival of the colony.

© Scott W. Michael

WHY DO FISH JUMP OUT OF OUR AQUARIUMS?

2011-12-19T13:23:00.000-08:00

Notorious jumper - the longnosed hawkfish.

I had a fish jumping incident happen recently that was difficult to comprehend. A client had a longnose hawkfish (Oxycirrhites typus) that had been in his aquarium for over a year. It was a “happy” fish that seemed to live a copasetic life with its tankmates. While working on the tank, I broke a small portion of the glass top (this resulted in an opening about four by three inches in the front portion of the cover). Before I could replace the top, the hawkfish was found dried up on the office floor – it had jumped out. I was perplexed as to why the fish jumped and how the fish was able to detect the hole in the top that had not been there for its first year in the aquarium?

Some fishes that are well known for jumping out of aquariums include: morays, snake eels, garden eels, anthias, hawkfishes (especially the longnose hawkfish), jawfishes, tilefishes, wrasses, sand perches, gobies and dartfishes. Morays are by far the worst jumpers. These fish will push their head from the water as they swim along the water’s surface and appear to test the top for openings. If there is an aperture, they are likely to find it and slither out of the tank. Not only will they leap from an open tank, large eels will occasionally push off aquarium tops to facilitate escape. In the case of these animals it may be necessary to place weights on the top to prevent this from happening (of course, make sure the weights you use are not so heavy that they break the glass – I use two pound weights for a diving weight belt). Morays apparently slither out of their aquarium home as they search for happier hunting grounds.

Some other renowned jumpers include certain wrasses, especially the fairy wrasses. A late friend, Bill Gordy, had an extra-large tank with numerous fairy wrasses. On several occasions, he had fairy wrasses leap from the tank when he removed the glass top and turned to clean it in a nearby sink. On his way back to the tank with the cover, he would find a fairy wrasse or two flopping around on the floor! Obviously, the wrasses were able to perceive (see) when the top was removed and they would then begin their aerial antics. Why? Who knows! Maybe they couldn’t stand the aquarium décor? It is true that male fairy wrasses tend to jump out of aquariums more often than females because they engage in a vertical swimming display that often results in their propelling themselves against the glass top or out of the tank if a top is not present. Male fairy wrasses have also been known to collide with and break metal halide lamps when they jump.

Jawfishes also regularly leap from aquariums. Like many other leapers they are experts at finding the smallest opening in the aquarium top to jump through. In most cases, jumping occurs before they find an appropriate location in the aquarium to dig their burrow. This is often during their first night of captivity. It is a good idea to leave the light on (that is, if it does not contain live corals) until the jawfish is able to create a suitable burrow.

A lot of fish jumping occurs after dark. This is probably a result of the quiescent fish being startled by another organism in the tank. In an attempt to escape, the fish races vertically up into the water column. The problem is, they are in a glass box not in the ocean! They end up hurtling out of the tank and onto the carpet. Many have employed a small night light over the tank to help reduce the possibility of jumping. Another time when fish are likely to leap from their glass home is when they are being incessantly attacked by aggressive tankmates. If you have a potential leaper that is being picked on, you are going to find that fish on the floor if there is any way for it to leap from the tank.

Not only do fish leap from tanks, they sometimes leap into overflow boxes. If you have an overflow box built into the corner of your aquarium, make sure it holds two or three inches of water so that these fish can survive until you find and remove them.

FLATWORM WORRIES

2011-12-09T11:38:00.000-08:00

Acoel flatworms can reach plague proportions in the home aquarium. The photos shows Waminoa flatworms on a bubble coral.

The acoel flatworms are some of the most primitive animals on the planet. They actually lack a body cavity and a gut. Most of the flatworms we encounter in the aquarium trade are innocuous, causing no harm to corals. The acoels that are most often encountered living on mushroom anemones, soft corals and large-polyped stony corals are reported to graze on minute crustaceans, algae and detritus that adheres to the mucus of these cnidarians. When in small numbers, they do not appear to harm their host, but severe infestations can interfere with the photosynthetic activity of the zooxanthellae-hosting corals they infest.

Chelidonura varians is a flatworm assassin that will slurp acoels off of the substrate. Once the flatworms run out, it is going to starve to death. Do not mistake this species for Philinopsis gardineri pictured below, which does not eat flatworms.

Flatworms are easily transferred from an infected tank to a non-infected one on equipment and on live and dead substrates. If you buy a coral from a tank that contains them, you will want to try and remove them off before placing that coral colony in your display aquarium. There are a number of ways to do this, including siphoning the flatworms off the coral, dislodging them by swishing the coral colony back and forth in a bucket of tank water or by blowing them off with a powerhead, or by giving the coral colony a freshwater dip (usually no more than 10 seconds in freshwater that is the same temperature and pH of the aquarium water). The later can have deleterious affect on soft coral. There are also some liquid remedies available on the market that can be used to rid new cnidarian colonies of flatworms. However, if they are not used correctly (and even some times when they are) they can cause serious problems in your home aquarium.

There are a number of fishes that have been reported to feed on flatworms, including leopard wrasses (Macropharyngodon spp.), Halichoeres wrasses (Halichoeres spp.), tamarin wrasses (Anampses spp.), lined wrasses (Pseudocheilinus spp.), mandarin dragonets (Synchiropus spp.) and certain gobies (e.g., Amblygobius spp.). Do not expect any of these fishes to decimate a major flatworm infestation. It is best to place them in the tank before flatworms become a problem.

A Chelidonura varians imposter! Notice the difference in the "head"and "tail" shape of this non-flatworm eating species. This is Philinopsis gardineri.

SLUGS TO THE RESCUE!

One of the most effective flatworm feeders is not a fish, but a beautiful sea slug named Chelidonura varians - known as the blue velvet headshield slug. This slippery beauty is a flatworm assassin! It will slide over the substrate, vacuuming up the acoels in its path. They have sensory bristles on eat side of the mouth that help them find their prey and they simply suck the flatworms into their mouth once they overtake them. Unfortunately, once the food runs out, these specialized opisthobranch will starve to death. If food is not in short-supply, or if they are not attacked by resident fishes (e.g., wrasses, sharp-nosed puffers) or sucked into filter intake tubes or into powerheads, the normal life span is short (around three or four months). They have been known to spawn in captivity, but raising the larvae is difficult. When they reproduce, they produce a white, wavy egg mass and the eggs embedded in this structure will hatch in three or four days.

There may be other members of the genus Chelidonura that feed on flatworms, like this beautiful C. hirundinina.

There are other members of this genus, some of which are stunning in color (e.g., Chelidonura hirundinina), that may also eat these flatworms, but to the best of my knowledge, they have not been employed in this capacity before. One word of warning: make sure you don’t mistake C. varians with the very similar Philinopsis gardineri in coloration and general form. In the later species, the “tail” is rounded and not as long and filamentous and it lacks the hammer-like head found in C. varians. The diet of the two species are very different – P. gardineri feed only on an unusual opisthobranch known as the bubble shell s (family Aplustridae), not on flatworms!

DEEP WATER DELIGHT!

2011-06-03T02:30:00.000-07:00

Cephalopholis igarashiensis (a.k.a., the garish hind) is an amazing grouper that is poorly known to aquarists and scientists alike because of its proclivity for deep reef habitats - it occurs at depths in excess of 250 feet and is most often found in excess of 400 feet. As a result, it is not likely to show-up in your local aquarium store anytime soon. This individual was selling for $ 6,000 at House of Fins in Greenwich Connecticut (sorry, this photo was taken a couple of years ago and the fish has since been sold). Virtually nothing is known about its biology. It has been reported from southern Japan, Taiwan, Guam, the south China Sea, American Samoa, Tahiti and Fiji. It reaches a maximum length of around 17 inches.

TANK RAGE!

2011-05-09T08:45:00.000-07:00

Reef fishes, like this dwarf hawkfish, comes into the tank with behavioral baggage that can cause problems in a captive fish community. Photo by Scott W. Michael.

One of the biggest problems encountered by marine fish keepers is aggression. It can cause disease and death, especially in newly introduced fishes. So how do we deal with it in our aquariums? There are several phenomenon related to animal ethology that we need to “unpack” before we try and solve our problems with “tank rage.”

The first of these is displacement behavior. Animal behaviorists have found that when the level of anxiety rises in an animal (including fishes) they may engage in out-of-context or irrelevant response as a result. For example, place a clear acrylic divider in a tank that contains a highly territorial species, like a Fiji blue devil (Chrysiptera taupou) – a particularly pugnacious damselfish. Now place a conspecific on the other side of the acrylic. The resident fish will display and attempt to get at the intruding blue devil. It will display and nip at the glass anytime the conspecific moves into view. As aggression and frustration escalates, the damsel may then engage in displacement behavior. This may include attacking a shrimp that shares its side of the tank or biting at the Caulerpa that grows throughout the aquarium. These behaviors do not help it to achieve its ultimate goal (that is, to get the intruder out of its territory), but by attacking the crustacean neighbor or “punishing” a plant, it releases some of the accumulating anxiety.

As time passes, the Fiji blue devil’s attempts to push its way through the clear acrylic divider will become more half-hearted. Agonistic displays will decrease in number and intensity and the frequency of displacement behaviors will subside. After a certain period of time (which is usually a function of the species in question and possibly the target of its aggression), it will get use to the releasing stimulus (that is, the intruder). This is known as habituation.

We can use habituation to our advantage when adding a new fish to a established fish community. You have quarantined your new fish and are ready to add it to your tank. But you are worried that upon entering its new environment, the newcomer will be accosted by the resident bullies. You can habituate aggressive residents to a newcomer by allowing the former to see, but not have access to the fish to be added. In the example above, I mentioned an acrylic divider. If your tank is small enough and you can section off a portion of the tank for the “newbie,” a divider like this will work well. Make sure the divider is perforated so that oxygenated seawater readily passes between the sectioned-off portion of the tank and the main aquarium. Of course, it is also important that the divider is see through. While reef fish can detect each other via other sensory modalities, visual contact is important to ensure habituation.

Another way to facilitate habituation is to place the new fish in a plastic basket or food storage container (e.g., Tupperware) that float at the surface of the tank. In the case of the basket, the holes should not be large enough for the acclimating fish to escape from but must be large enough so visual contact can occur between the “greenhorn” and the “veterans.” If you use the plastic storage container, it should be clear and must have holes drilled in it so water can freely circulate between it and the tank. If you can place it in a corner of the tank that is buffeted by pump output, there is more likelihood good water exchange will occur between the container and the tank. You can also use clear breeding traps that hang on the inside of the tank. These are typically designed to house freshwater livebearers, which are small. Therefore, they will only work for more diminutive marine species (e.g., dottybacks, damsels, gobies, blennies). Whatever type of “habituation pen” you decide to use, keep the new fish in the container for several days or until the aquarium residents consistently ignore it.

Since a territorial species will recognize its home by certain physical features, it is not a bad idea to rearrange the aquarium décor when adding a new fish to a tank that contains a potentially pugnacious resident. By confusing the “old-timer” the newly added fish may have a better chance of getting its own chunk of ground before the established resident gets reacquainted with its surroundings. Of course, many of us are not willing to rearrange our reef tank every time we add a new fish. We will have to rely on other techniques.

Remember that if important resources, like food and shelter, are in short supply, levels of aggression are likely to escalate. So, frequent feeding and plenty of shelter sites can be helpful in curbing some fish aggression. Space is also the aquarist’s best friend. The larger the tank, the less likelihood that aggression is going to cause you persistent headaches. One final thought, you should have a good fish trap at your disposal because sooner or later you are likely to have to remove a piscine sociopath.

© Scott W. Michael

LPS EYE CANDY!

2011-04-25T21:18:00.000-07:00

How is this for a collection of amazing large-polyped stony corals! The shot includes amazing corals in the genera Scolymia, Cynarina and Balonophyllia. While expensive, all of these amazing corals are fairly easy to keep if given enough light, some food and appropriate habitat (in the case of Scolymia and Cynarina a soft substrate to rest upon). This buffet of calcareous beauties was photographed at the amazing HOUSE OF FINS (owned by my friend Rob Bray) in Greenwich, CT. Photo copyright Scott Michael

Oh, What Blue Teeth You Have!

2011-04-11T15:33:00.000-07:00

Our clients love the harlequin tusk (Choerodon fasciatus)! And why wouldn’t they? They are indeed one of the most beautiful fish inhabiting the reefs of the western Pacific. The tuskfishes are members of the wrasse family Labridae and is the only member of the genus Choerodon that is found in the aquarium trade with any regularity.

This harlequin tuskfish is grayish to baby blue overall, with up from five to nine bars on the head and body. In juveniles, the bars are coppery orange or brown and there are two eyes spots on the dorsal fin and one on the anal fin. The pelvic fins are black. As the fish ages, the head and body bars become brighter orange with blue trim and the ocelli on the fins disappear. The rear portion of the body becomes darker and in some individuals the posterior body bars become paler. In adults, the dorsal, anal and pelvic fins are also red, while the tail is pale (often with a red rear edge) These fish have a somewhat viscous look because of the enlarged canine teeth at the front of the jaws. But rather than being white in color, their teeth are sky blue! Sam, these dental pigments typically become more intense as the fish gets larger.

There are apparently two distinct populations of harlequin tuskfish in the western Pacific. There is a northern population, which ranges from southern Japan to Taiwan (including the Philippines and Micronesia). Many of the individuals in the aquarium trade come from the Philippines. There is also a southern population, which ranges from Vanuatu and New Caledonia to Queensland, Australia. Individuals from the southern population often exhibit a more striking color pattern. For this reason, and the fact that fishes from this region are just more expensive, those individuals from Australia command a higher price. I should point out that paying more for individuals from Australia is worth it. Not only are they more attractive, they have better long-term survival rates than those from the Philippines. No doubt this is a function of how the fish are collected and handled prior to arriving at marine fish wholesalers. This medium-sized wrasse attains a maximum of 12 inches in length (reports in the aquarium literature that this fish attains 24 inches are erroneous).

This blue-toothed beast has a reputation for being rather pugnacious. However, I think some of this reputation is based more on its fearsome "grin" than a true desire to inflict harm. It has been my experience that this fish is usually not overly aggressive toward similar sized or larger fish tankmates. You can even keep it with small fish in a large tank with plenty of nooks and crannies that its more diminutive tankmates can seek shelter in if threatened. Obviously, a harlequin tuskfish is more likely to cause problems in a smaller tank and if they get the chance, they may prey on fish tankmates that are small enough to subdue. One other note, they are a greater threat to their aquarium tankmates as they get larger. There can also be differences between individuals - an occasional individual may be more ill-tempered than other members of its species.

In most cases, these fish are not picky about what they consume. However it is not unusual for a new tuskfish to refuse food for several days after it is introduced to its new home. When it settles in, it will eat with gusto! Feed them a varied diet (e.g., fresh seafood, prepared foods for carnivores – we love the Rod’s Food!) and make sure you include those foods with added pigments to facilitate color fidelity.

There are two things that make the harlequin tuskfish a bit of a husbandry challenge. First of all, it is imperative you start with a good specimen to begin with. Individuals that arrive in rough shape and never acclimate to captive living. The other problem is resident bullies. If your tuskfish is picked on, it will never adjust to its new home, will start skulking behind the aquarium décor and stop feeding. I will give you an example of the latter – we added a beautiful adult harlequin to an aquarium that was in excess of 300 gallons. As soon as the tuskfish was added, it was harried by a smaller adult Symphorichthys spilurus – the threadfin snapper. This later fish is rarely aggressive in my experience, but this snapper hated the harlequin tuskfish! Eventually, we removed the tuskfish but it was too late. It had gone too long without eating and eventually perished.

The harlequin tuskfish feeds on mollusks, crustaceans, worms and echinoderms. However, they do not eat coral (they may move coral colonies when looking for hidden prey). You will have to make a decision if you want to keep snails, small clams, ornamental shrimps, sea urchins or sea stars. If you want to house these inverts in your reef aquarium than you better stay away from a harlequin tuskfish. Note, these fish are much less destructive as juveniles than they are as adults. Also, it would be fool hardy to place more than one in the same tank, unless the aquarium is huge. Unlike some wrasses, be aware that tuskfishes do not bury under the substrate at night or when threatened.

© Scott W. Michael

WELCOME!

2011-04-11T11:57:00.001-07:00

Welcome to the Reef Tectonics Blog! We hope that this blog will enable us to communicate with our valued clients as well as anyone that loves aquatic organisms and aquariums! We welcome your feedback on the subject matter discussed on the blog and suggestions on future contributions. You can also visit our website (www.reeftectonics.com) and our facebook page! Happy fish-keeping!