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Issue: April 2014

The Tiny Titan of Lake Tanganyika: Lamprologus Ocellatus (Full Article)

Author: Samuel Magaziner


Photographer: aquariumphoto.dk
An experienced cichlid breeder details the care and breeding of a charming shell-dwelling cichlid from Lake Tanganyika with fascinating behaviors and interesting looks.

Among the many cichlid species from the rift valley regions that I have kept, I find the shell dweller Lamprologus ocellatus to be one of the most endearing and enjoyable species to raise. I first came across this fascinating species several years ago, in 2008, while scanning through my copy of Dr. Axelrod’s Atlas of Freshwater Aquarium Fishes (TFH Publications, 1985). As I was aimlessly leafing through the various fish species that filled each page, I paused at an entry containing what I thought (at least at the time) to be an adorable, mottled-gray, alien toad fish. For indeed, the protruding eyes, goby-esque shape (common to most bottom dwellers), and baby-like appearance, with its oversized head seeming too large for its small body, lent the fish an alien air. This first encounter was to spark a journey.

Several years later, in 2011, I had the joy of once again stumbling upon this shell-dwelling species, though this time at my local fish store. Naturally, I purchased the group (at the time two adult males and one adult female, all wild caught and of the Zaire blue variety), and thus began my adventure with these tiny titans.

Geographic Distribution and Physiology
L. ocellatus is indigenous to Lake Tanganyika, one of the great rift lakes of Africa—landlocked seas, so to speak—where isolation and unique environmental conditions have led to a wealth of aquatic biodiversity and the vast differentiation of species, each with a unique niche within the lake. Lamprologus ocellatus, sometimes commonly referred to as the frog-faced cichlid (for its aforementioned protruding eyes and sloped forehead), is certainly no exception.

This species inhabits the littoral regions of the lake where fine sand beds or muddy bottoms are strewn with the empty shells of the native snail, Neothauma tanganyicense. It has evolved over time to utilize these shells for the purposes of dwelling and breeding, hence the common name “shell dweller.” It is an interesting facet of evolution to behold, for just as a hermit crab might abandon a shell that has grown too small, L. ocellatus will similarly move to shells of increasing sizes until it finds one fitting of its adult size. Unlike a hermit crab, this shell dweller will defend its abode much more fervently, not retreating into its spiral shelter at the sign of an intruder, but flaring its fins and nipping at species several times larger than itself. It will also attack the occasional gravel vacuum or stray hand, as firsthand experience has shown, with nipping, at times, vicious enough to draw blood! Now, this is no small feat, for the species itself maxes out at around 2 inches (5 cm) with females being slightly smaller, typically measuring in around 1½ inches (4 cm).

L. ocellatus is typically colored a mottled gray with a dazzling patch of iridescent blue on its side. Its dorsal and anal fins, depending upon the individual, are lined with white, orange, or a combination of the two. There’s also a stunning gold variety of the species that possesses a luminescent soft-yellow body in conjunction with the blue patch as opposed to the ordinary dappled gray. The species is rather streamlined, possessing protruding eyes and a sloped forehead, all hinting at its benthic lifestyle.

Temperament and Aquarium Care
In aquaria, L. ocellatus makes a fine addition to any Tanganyikan community or can even be enjoyed within a species tank all its own. Indeed, I first placed my trio in a 10-gallon species-only tank.

The tank had a fine sand substrate strewn with shells. A sand substrate is not absolutely required, as it might be for some species of featherfins or open-sand dwellers (in fact I have successfully kept this species with a river gravel substrate), but I have found that a fine sand substrate elicits some of Lamprologus ocellatus’ most intriguing traits. This species has developed a mechanism in which it propels itself into the sand around its shell head first, with mouth wide open, and moving at great speed. In the process, it jettisons the sand through its mouth and out its flared gills, thus moving large quantities of substrate. This creates ditches around the shell, into which the shell then falls, adjusting its position. It will do this until the shell’s open face is positioned in such a way that is favorable to the fish. L. ocellatus will then proceed to bury the rest of the shell, leaving only the opening of its shell above sand.
It has been suggested that the purpose of this behavior is twofold. One, the process usually creates a rampart of substrate leading up to the shell, adding to the fish’s capacity for territorial defense. Two, the cichlid positions the shell aperture in a manner that ensures a favorable flow of water and, in the wild, plankton into the shell, which is an important aspect of survival for newly born fry.

In my experience, when first introduced to a tank, a group of L. ocellatus will jostle back and forth, fighting for the territory within the tank that provides the most favorable flow, typically near a filter intake. The fish that achieves this spot will typically be the tank’s alpha male (assuming more than one male is present).

As previously stated, in my 10-gallon tank, shells littered the tank floor. For this particular species, the presence of at least one shell per fish is vital. Unlike some colonial species, such as Neolamprologus multifasciatus, vast shell beds are not required. Rather, each individual will dwell primarily within one shell, protecting any others that might lie within its territory. If shells are not provided, the fish will feel vulnerable and, as such, will behave skittishly, hiding in the tank’s upper corners or diving into the sand, burying itself completely if startled.

I quickly found out that proper distribution of shells is just as important as ensuring their presence in the tank. You see, L. ocellatus tend to stake out a territory within a 6-inch (15-cm) radius from what I like to call their home shell, the one in which they dwell the most. Any shell or object to fall within this territorial range will be defended with zeal, a vigor unexpected and indeed entertaining from such a small cichlid. I have witnessed in my own community aquarium an adult male defend his territory from a full-grown, 5-inch (13-cm) Altolamprologus calvus and win the day!

It is entirely possible that if clustered together, one fish can lay claim to every shell within the tank, leaving others of the species ostracized to the corners of the tank and skittish. Thus, whenever a group is kept together, the spacing of shells must be taken into consideration (bearing in mind the typical 6-inch [15-cm] stake of territory). In the wild, L. ocellatus primarily dwells within the shells of Neothauma tanganyicense that litter the lake floor. However, in the home aquarium, I have found that escargot shells (cleaned out, of course) from your local supermarket will eagerly be accepted as substitutes for Neothauma tanganyicense shells.

Being denizens of Lake Tanganyika, these fish will appreciate alkaline, well-oxygenated water with a temperature in the high 70s to low 80s Fahrenheit (about 25–28° Celsius). As with most African cichlids, I have found L. ocellatus to be rather hardy and thus not particularly sensitive to middling levels of nitrates and trace amounts of ammonia. However, the fish will do best and show their brightest coloration in water with minimal pollutants.
L. ocellatus is readily available for purchase as captive-bred specimens that will accept a wide variety of flake and pellet foods. As carnivores, the fish will appreciate frozen mysis shrimp and live or frozen brine shrimp every now and again. This works particularly well to season them for breeding.

Breeding
L. ocellatus is a harem breeder, meaning it is most successfully kept in groups, with two or three females for every male. However, a pair can be successfully contained in a 10-gallon tank. Indeed, when I received my first trio, within a week, the female and one of the males had each laid claim to half the tank, leaving the third male to hide, beaten up, in the corner. Subsequently, I was forced to remove him from the tank. Were one to keep a trio, I would recommend a tank no smaller than a 20-gallon long (footprint of 30 by 12 inches [75 by 30 cm]). Not only would this size tank give the fish optimal room, but it is also large enough to house at least one generation of fry. Keep in mind that with this species being a substrate dweller, the size of the floor plan is more important than the volume of the tank.

The best way to form a pair is to buy a group of four or five juvenile fish, grow them out in the same tank, and wait for pairs (or trios, should one desire a larger colony in a larger tank) to form naturally. However, should such a method prove undesirable, it is possible to buy one male and one female, hoping that they will pair off. In my experience, this is a hit-or-miss method. At times, I’ve had a successfully breeding pair form, and at other times, one fish or another would end up ostracized in the upper corner of the tank and would have to be removed.

Sexing L. ocellatus without venting (which is difficult due to the small size of this species) is simple if the group at which one is looking is composed of individuals all the same age. Males typically grow larger and faster than females and thus would be the largest individuals of a group the same age. Moreover, males are typically more territorial than females, vehemently chasing intruders in their territory, while females will flare up but will not so enthusiastically engage the interloper. Lastly, females tend to have more white-tipped dorsal and anal fins while males have orange-tinged fins. However, I have seen some males with a striking amount of white, so this is only a rough indicator.

To induce spawning, it is best to maintain high water quality through weekly partial water changes and the avoidance of overfeeding. In the past, I have found that by offering L. ocellatus live prey (brine shrimp primarily), as well as a balanced diet of flake and pellet food staples with high-quality frozen food, females will reach spawning condition quicker and produce more eggs per batch then those females receiving only flake and pellet food. As the pair that I first kept in my 10-gallon were already adults, signs of courtship could be seen within one month of purchase.

To initiate spawning, the female will darken along her back and initiate a courtship dance, in which she curls her back and slaps with her tail in the male’s direction. She then proceeds to go into the shell and lay her eggs. Next, the male will swim over to her shell and either enter the shell, fertilizing the eggs with his milt directly, or, if too large to enter the female’s typically smaller shell, he will just deposit the milt over the opening of the shell, trusting the water’s flow to induce fertilization. At this, the male and any other trespasser will be chased away by the female, who keeps guard over the deposited eggs. The eggs themselves are never seen by the aquarist, and thus it is entirely possible that one might not even know one’s fish have bred.

Care of the Fry
Within 72 hours, the eggs will hatch into wrigglers, and within 10 days following fertilization, the fry will be free-swimming. The fry themselves will first appear as microscopic pinheads, darting across the surface of the sand, but will eventually grow into little replicas of their parents. Batches of fry can range in size anywhere from 15 to 70 (approximately). The size of each batch depends upon the size and age of the female as well as the quality of her diet. Typically, younger and older females produce fewer eggs than those in their middle years.

The fry can either remain with the parents or be transferred to a grow-out tank. In the first couple weeks, the fry will barely venture out from the mother’s shell and will flee into it at the first sign of danger (following the mother herself as she dives into the shell). Thus, removing them from the tank before this time proves difficult without injuring either the fry or the mother. It should also be noted that first-time parents are prone to eating either the eggs or newly hatched fry, but their parenting skills will grow with time. I was lucky enough that such activity did not occur with my pair’s first brood. However, with subsequent pairs (not the wild-caught pair), I witnessed the parents cannibalize the fry on several occasions.

Now, at this point, when you first see the fry poke their little heads out of the shell, they must be fed their own specific diet. I have been very successful with freshly hatched brine shrimp nauplii. You can either deposit the nauplii straight into the tank or, using a turkey baster, gently squirt the shrimp mixed with tank water into the opening of the shell to ensure that the fry receive the food. Another option is to take the pellet and flake food given to the parents, grind it up using a mortar and pestle, creating granules small enough for the fry to eat, and distribute it using similar methods. Regardless of whether you’re feeding the fry in the parents’ tank or a grow-out tank, I recommend turning off any filters or powerheads when feeding to ensure the food is not swept away before the fry have a chance to eat it.

After three weeks or so, the fry will no longer reside in the mother’s shell. They’ll first hover over the sand bed, only to take up residence in an unoccupied shell a little time after. Juveniles will be mostly ignored by the adult fish, but in smaller tanks they will have to be removed until they reach an adult size in order to avoid excessive aggression. Moreover, even with juveniles in the tank, the adult pair will continue to spawn. Eventually, the older siblings will prey upon newly hatched, free-swimming fry. At this point, if one wishes to resume successful breeding, either the pair or the older siblings will have to be moved. In larger tanks, huge colonies of this fish spanning several generations can be maintained as long as shells are continually available. However, as with smaller tanks, eventually the population will reach saturation and cannibalism of younger siblings will ensue.

Tiny Titans
If there is anything this fish might lack in color or size, it makes up for it in sheer tenacity and personality, a titanic soul encapsulated within the smallest of bodies. Whether it’s the vigorous defense of a territory, the rearranging of shells, or the rearing of fry, this species has plenty of interesting behaviors to offer any true enthusiast. The sheer energy of this little lamprologine is enough to make anyone fall in love with it. I wholeheartedly encourage those new to the cichlids of the rift valley lakes as well as seasoned cichlid veterans to try their hand at keeping this tiny titan, the endearing shell dweller Lamprologus ocellatus.


See the full article on TFH Digital http://www.tfhdigital.com/tfh/april_2014#pg55

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