The African Butterflyfish Pantodon buchholziAuthor: Ted Judy
West Africa is a region rich in unique aquarium fish. Many of the oddball species familiar to most aquarists, including leopard leaf fish Ctenopoma acutirostre, bichirs Polypterus spp., various mormyrids like elephantnoses and baby whales, and the large freshwater puffers Tetraodon spp. all come from this region. One of the most unique species is the African butterflyfish Pantodon buchholzi.
The butterflyfish is a distant relative of arowanas and other bony-tongue fish. P. buchholzi is a top-oriented species that swims just beneath the water surface. The fish is flat on the top with a blunt face and deep body, with an array of finnage that extends down and away from the surface. The pectoral fins are enlarged and extend outward from the side of the body, suggesting the “butterfly” part of its common name when seen from above. The ventral fins are reduced to thread-like extensions that project down below the body like an empty fan. The anal fin is large and, with the broad caudal fin, helps to propel the fish out of the water with powerful motions for capturing insect prey above the water surface. The color pattern is a gray and brown camouflage pattern.
Butterflyfish are efficient ambush predators that specialize in eating terrestrial insects that fall to the surface of the water or are low enough to be plucked off of branches or leaves after an accurate leap. They are powerful jumpers, and therefore a tight-fitting lid is required in an aquarium setting. This feeding strategy is supported by large eyes that sit high on the head near the water’s surface, and a very large upturned mouth—similar to an arowana’s—that can engulf large prey.
In the aquarium, the fish will learn to eat a wide variety of floating foods such as sticks and pellets, so long as the food is substantially large enough attract their attention. The best food, especially for conditioning the fish to spawn, is live crickets. The normally sedate butterflyfish can sense the movement of a cricket on the surface of the water from across a large aquarium and quickly hunt it down.
Natural habitats for P. buchholzi are quiet ponds, marshes, flooded areas, and quiet backwaters of streams and rivers. They seek out floating structures, particularly plants, which may harbor prey in the leaves and stems above them and grant them protection from the eyes of predaceous birds. Their movements are slow and deliberate in order to avoid detection by either predator or prey, but they can move very quickly to attack any small creature that attracts their attention.
Aquariums should be quiet and without a lot of water movement. Wide ranges of water conditions are tolerated so long as the water is not very hard and basic. Soft, slightly acidic water is better for spawning and rearing fry, but moderately hard water with a pH in the 7.0 to 7.8 range is acceptable to keep butterflies happy and healthy.
P. buchholzi does not need a lot of space, but if they are to be kept in a West African biotope community, an aquarium 30 gallons or larger will permit a larger variety of fish to live with them. Tankmates should be chosen with care. Though butterflyfish are not efficient fish predators, small fish that venture too close to their mouths will be eaten. Larger tetras and barbs are safe from predation. Small bottom-oriented cichlids, catfish, Ctenopoma species, and mormyrids are also excellent choices. Also be aware that fin-nippers should be avoided, since they will attack the long, flowing fins of the butterflyfish. The light should be subdued because the butterflies live so close to the surface, so low-light plants of the genera Anubias, Bolbitus, and Cryptocoryne are the most appropriate.
Butterflyfish are not aggressive with each other except during courtship and spawning. Males and females can be distinguished by their anal fins. While a female’s fin is broad and unbroken, a male’s fin is separated into two distinct sections, with the lower portion being longer than the upper portion. Females also grow larger and heavier than the males. Coloration is highly variable and not a good indicator of sex. Several fish can be kept together, and they will even school in rafts of butterflyfish, all in one spot.
Eventually the males will isolate themselves into small territories, which they will defend from other butterflies. The contests are not violent, however, and result in nothing more than the invader being pushed away. If there appears to be too many fish in an aquarium to allow each to have its own small space, a few should be removed. A tank with a 24- x 13-inch surface area (a standard 20-gallon-high or 15-gallon aquarium) is plenty of space for a pair or trio.
Inducing healthy butterflyfish to spawn is not difficult. The usual trigger is a cool water change. The opaque white eggs, which immediately rise to the water surface, are laid in floating plants. They turn dark after 24 hours and will start to sink. The large eggs take about seven days to hatch. There is no parental care for the fry, and the parents are likely to eat them. If the goal is to raise butterflyfish fry, the best method is to remove the parents from the tank when eggs are present.
Rearing the fry is more problematic than getting the eggs to hatch. The baby butterflies are not very mobile and are not very good at hunting food. Newly free-swimming fry resemble their parents only in color. Their fins are not well developed at all, and they appear similar to skinny frog tadpoles. The only clearly distinguishable features are the eyes, which are large and clear from the start. After the fry hatch, they rise up into the floating plants and take up a position in which they will wait for food to come to them. They will only eat live food that comes within striking range, and they may not even strike the food unless it touches them on the face.
The most challenging part of raising the babies is getting them enough food. They are too small to take insects like wingless fruit flies or pinhead crickets at first, and any food that drops below them will not be eaten. Baby brine shrimp Artemia nauplii is an excellent first food, but they will not live a long time in fresh water. Daphnia or Moina (similar to Daphnia but smaller) are better choices because they will not die, but the trick is to keep the food in front of the fish for as long as possible. The best way to accomplish that is to drop the water level to the point where the floating plants are resting on the bottom. A ½-inch-deep water level is not too shallow. With the water level that low, the live food cannot swim below the fry. A dense cover of floating plants also traps the live food in small spaces with the fry, allowing the fish to easily find the food. If brine shrimp is used, the water will have to be changed frequently, which is best accomplished by adding aged water to the tank, letting it sit for a few minutes to mix, and then lowering the water back down to the shallow level.
The fry will grow quickly once they can easily find food. The next challenge is to keep them from eating each other. It is not uncommon to get 100 or more fry from a single spawn, and the close contact with siblings increases the opportunities for cannibalism. The fish will strike instinctively at anything smaller than they are that bumps into them. Larger fry will not hesitate to eat a smaller sibling, which will make the eater grow much faster and more capable of eating more siblings. The result will be a group of 100 fry being whittled down to just a few.
This process is very natural, however, so unless the goal is to end up with many butterflyfish, the cannibalism is actually a good way to end up with a few larger, healthy juveniles. The only way to reduce sibling predation is to reduce the density of the population. When the fry are about a week old, they can be separated safely into other tanks with fewer fish per tank. They will still eat each other, but the lower density results in fewer incidents of cannibalism.
The fry will start to grow their distinctive pectoral fins at about two weeks of age. They will now be a little over ½ inch long and able to eat larger food items. Wingless fruit flies and pinhead crickets are excellent for this stage. Daphnia and baby brine shrimp can still be fed so long as the water remains shallow. When the fry are about six weeks old and over an inch long, they will start to eat small floating pellets and freeze-dried foods. This may take some training by feeding pinhead crickets or fruit flies along with the pellets. As the fish aggressively feed on the live food, they will also take some pellets and learn that it is food.
A 12-week-old juvenile looks and behaves like a miniature adult. The risk of cannibalism is greatly reduced after this point, but putting them in with adults is probably not a wise thing to do. After a few months the young adults can be put into community tanks to grow and prosper. P. buchholzi is slow to mature, and it is unlikely that the new generation will try to breed until they are a year or more old.
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