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Opthalmotilapia heterodonta
by Diane Tennison

Fin Organism Water Fish Underwater

Opthalmotilapia Heterodonta, originally described by Max Poll and H. Mattes in 1962, is a very close relative to Opthalmotilapia Ventralis. These maternal mouthbrooders hail from the northern part of Lake Tanganyika. I successfully raised and spawned a group from the Nyanza Lac region of Burundi. These fish are typically found in the intermediate habitat, between rocks and sand, at a depth of 1-6 meters. Their native condition is in water that ranges from 24-27 degrees C and with pH between 7.8 and 9.5. As these fish can get quite large (6+" on the males and 4+" on the females) - I would recommend nothing shorter than a 5 foot tank. They also need quite a bit of swimming room because, while not an overly aggressive fish, they do chase each other alot as they become sexually mature. I had my colony in a 6 foot 180g tank and they thrived. Regular water changes are very important to maintain good growth and health with Heterodonta. I maintain weekly water changes of 25% to 30% of total water volume. These fish are fairly sensitive to poor water conditions and can be the first to go if your tank conditions crash. They also do well with tankmates. I had my colony in with a growing group of Frontosa and a few odds and ends (from Malawi Peacocks to a lone Calvus). I think the other tank inhabitants helped to keep the aggression down within the colony of Heterodonta. It is also recommended to keep several females to 1 male. However, to have successful spawning - it is recommended that your colony have at least 2 males. Lone males tend to get lazy and are not "inspired" to spawn. In the wild, Heterodonta, like most Tanganyikan Featherfins, prefer a varied diet - typically zooplankton and some vegetation with items such as diatomic seaweed. My colony was fed a rotation of NLS Cichlid pellets, Dainichi Veggie FX, frozen Krill and frozen Mysis.

Water Organism Fin Fish Underwater

I first received my group of 6 fish as juveniles. They were, at the time, mis-identified as Opthalmotilapia Ventralis. Only when the dominant male flashed breeding dress was the difference noticable. The Ventralis from the Nyanza Lac region is a fairly boring variant of Ventralis - sporting a solid charcoal grey coloration when courting females. The Heterodonta from the same region is a whole different story! The male, when courting females, is a beautiful steel blue color with intense - almost neon - powder blue in the fins. The fish is beautiful in person, but a photograph really brings out the intensity of the color. As with most Featherfins, my juveniles went into the tank as 6 silver fish. When photographed, or spotlighted, they displayed a green sheen with a rim of yellow along the top of the body. This coloration was not visible with the naked eye. There was no difference, or sexual dimorphism, between the males and females at the juvenile stage. They were fairly quick growers and soon attained adult size (within 6 - 8 months) but remained silver. The males were easy to spot as their pelvic fins are long and flowing and have bright yellow tips. Even though I could readily identify the dominant male (I had the amazing luck of having my colony consist of 2 males and 4 females) by his behavior, his color remained silver. If he was agitated, he would get a slight grey hue to his entire body, but that was the extent of his coloration. They took almost 2 years to sexually mature and feel comfortable enough to spawn. My tank was arranged with rock work on both ends of the tank and an open center. I came home one day to find that the dominant male had begun his bower. In typical Featherfin fashion, the males will build a bower - or spawning pit - spending hours taking the sand from the depression and depositing it along with rim to make a bowl shaped indention in the sand bed. It was built against the back wall of the tank. In the wild, these fish will build their bowers up against a rock - thus using the rock as a shield from predators or disruptions to the spawning process. While he built an impressive bower (a good 9" to 10" in diameter and 2" deep) - the females were NOT interested.

Fin Fish Marine biology Rectangle Tail

He would spend all day, perfecting his art and the females (along with the sub-dominant male) would cluster near a rock pile and watch. He would dart out and try to woo a female over and he was constantly ignored. Their luring behavior is different from most other mouthbrooding Cichlids. Most fishkeepers will recognize the typical spawning "shimmy" of the mouthbrooder. Heterodonta does things differently. They will aggresively approach the school of females and then the will quickly turn and swim back to the bower. While swimming, the fins remain clamped and the male "swishes" back and forth in a side to side fashion. This is to spread his scent back to the female so she knows to follow. This behavior went on with no success for over a month. The male would continue to construct and perfect his bower and the females would continue to ignore him. However, his hard work finally paid off. I came home to see him in the splendor of his full breeding dress! I quickly ran for my camera. This time one of the females was interested. Unfortunately, I did not witness the actual spawn. I did, however, notice that one of the females was holding a mouthful of eggs. Research described the actual spawning process. Once inside the bower, the male will circle and shake a bit - very close to the sand - dragging the yellow tips of his pelvic fins along the bottom. While he circles he will release some milt. The female will pick at the false eggs, bringing some of the milt into her mouth. She will then circle and lay eggs, picking them up as soon as they are laid. She will continue to follow the male, alternatively picking up her own eggs and picking at his pelvic fins - thus fertilizing her eggs with his milt.

The female held the developing fry, quite comfortably in the community setting, for 14 days before I made the decision to strip her. In the wild, or left to her own devices, females will usually hold for around 3 weeks. I was rewarded with 10 fully formed fry with just a bit of egg sac remaining. Typical spawns from experienced pairs will yield 14 to 20 eggs. The fry were easily ½" to ¾" long at this stage. I put them into an acrylic breeder box and floated them in the tank. I placed a bit of sand in the bottom of the box to help disguise them from the adult fish swimming below. I began to feed them freeze dried Cyclopeeze when the egg sac was completely absorbed. In the wild, when the fry are released from the mother, they will gather in schools and congregate in the upper portion of the water column. It is not uncommon to find the young Heterodonta swimming with other juvenile cichlids of various species.

Water Vertebrate Underwater Organism Fish

Opthalmotilapia Heterodonta is a beautiful fish that is fairly easy to keep. This relatively peaceful Tanganyikan Featherfin makes a wonderful addition to a long tank. It is also fascinating to watch the spawning behavior, but patience is a must. I highly recommend this fish if you are able to find them in your area or have them shipped to you.
Eye Plant Petal Tints and shades Font

Originally published in The Lateral Line, the official publication of the Hill Country Cichlid Club.
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