bitteraspects
Fish Herder
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Common Name: Bucked tooth tetra
Classification: Exodon paradoxus
Family: Characidae
Origin: South America. Exodons were originally discovered widespread throughout the Amazon basin and in the Orinoco basin within South America. It is widespread throughout the Brazilian Amazon basin and has also been recorded in the Rio Branco in Guyana.
Habitat: Usually found in parts of rivers flowing through savannah-like grassland. These biotopes are characterized by flowing waters over sandy substrates.
Size: In the wild Exodons are known to grow as big as 6". However, you will rarely see them larger then 3" in an aquarium. 4" is considered large in a home aquarium.
Minimum Tank Size: A 48" x 18" x 18" (120cm x 45cm x 45cm) - 225 litre/60 gallon tank is suggested to house a shoal of these fish. In anything smaller, however it really depends on how many you plan to stock.
Tank Setup: A biotope setup would consist of a substrate of sand with perhaps a few driftwood branches and roots added for effect.However, the fish are most at home when kept in a heavily planted tank. This kind of setup has the added benefit of containing plenty of refuge where individuals can go and seek some respite if they are being singled out for bullying. Filtration should be very efficient to cope with the fact that the species needs to be maintained in large groups.
This is an example of a natural biotope for this species:
Temperature: Exodons thrive in tropical temperatures of 78-82°F. However, they are pretty tolerant when it comes to temperatures as low as 70° and over 85°.
pH: Exodons can be naturally found at the range of pH 5.7 - 6.2 but can be found closer to ph 7 in home aquariums. This is a hardy species that is
easily acclimated.
Hardness: 0-20°dH
Description: Exodons are little fish with brilliant coloration. The caudal fin is yellow and the other fins are red to red tinting. They have two very large dark spots, one in the humeral area in front of the dorsal fin level and the other one covering the whole height of the caudal peduncle. They often have a slight blue to purple tint over their entire body with the females looking more yellow.
Diet Gut analyses of wild specimens have shown that the diet consists largely of insects and the scales of other fish. Thankfully, there's no need to
provide live fish in captivity as dead alternatives are readily accepted. Feed a varied diet comprised predominantly of meaty fare such as bloodworm,
chopped prawns, mussel, earthworms and lancefish. Most will even accept dried foods. Ensure that other tankmates are receiving enough food, as Exodon are
violent and greedy feeders. Stories have it that locals living in areas where the species is common place dirty pans and dishes into the water and the fish
perform a useful task by picking every scrap of food from them!
Compatibility These fish are found in the same areas inhabited by Fire Tetras (Hyphessobrycon amandae), Red-eyed Moenkhausia (M. oligalepis), two Corydoras species (Corydoras julii and C.nanus)and small sucking catfish (Otocinclus affinis). When kept in groups these will be fine to keep with Exodons. However, this is not a community fish in general and is best kept in a species setup. It will relentlessly attack any silver-coloured or shiny tankmates, stripping them of scales and fins very quickly. Some larger predatory species may not eve be safe. Scaleless and non-reflective fish are generally left alone. Success has been had keeping Exodon alongside various loaches, loricariids and some larger characins such as Anostomus. The situation will always be somewhat unpredictable though. It's best to add the Exodon last as they may see any new additions as food. With most predatory species they tend to bite
first and ask questions later.
A minimum of 8-10 individuals is usually recommended but buy as many as the tank can house. Generally, this is not a cheap fish at an average price of $7-8/ea. You can sometimes find them as low as $3-4 with a little luck. Be prepared to lighten your wallet a bit if you plan to keep Exodons. In a tank like the one described above a group of 25-50 would not be an unreasonable number. If kept in smaller groups, they tend to pick one another off until only a single fish remains. and a single Exodon will likely die of the stress from being alone. In large shoals, no individual can be targeted and it is usually only sick or unhealthy specimens that are killed. Occasional losses should still be expected. The interaction of a big group is fascinating to watch especially at feeding time.
You should buy the entire group at the same time since new additions are usually attacked. If you decide to add to your shoal after the initial group you should
add them in a group of 5 or more. A single introduced fish may be seen as food and killed before morning. It is also suggested that you do a water change prior to adding the new Exodons to the tank. This will help to distract the shoal.
Sexing: Mature males are slimmer than females. The females tend to be broader and wider and have slightly elongated dorsal and anal fin rays.
Breeding: Breeding has been achieved but on rare occasion. It's an egg scattering species. The best way to approach a breeding project is to set up a separate tank in which to spawn the fish. Something around 24" x 12" x 12" in size should be sufficient. This can be empty save for some clumps of fine-leaved plants to catch the eggs. Alternatively, cover the base of the tank with marbles or similar round stones. This should be big enough so that fish eggs can fall through it but small enough to prevent the adult fish from reaching them. Water should be soft and slightly acidic (pH 6.0-6.5, gH 1-5). Meanwhile, condition
the adults in a shoal in a separate tank as described above.
Once the fish are in good condition, select a pair and transfer them to the spawning tank. This can take a few tries as it is difficult to determine whether
or not a breedig pair has been established. Apparently, spawning can sometimes be initiated by performing a large 50%+ water change with slightly warmer
water than that in the tank. Remove the adults as soon as eggs are noticed since they will eat their spawn given the opportunity.
The eggs hatch in as soon as 48 hours and up to 3 days. There is little information available regarding the raising of the fry. It's likely that small live foods such as newly hatched brine shrimp will be accepted. Cannibalism will probably be rife so keep a close eye on the young as they grow and have several tanks ready to move differently sized fish into.
Other Notes: The genus Exodon is currently monotypic with this single species having uniquely designed teeth. The mouth of the Exodon is terminal and scarcely oblique; its pre-maxilla has an ascending process with 3 outer tusks and 6 inner acute. The maxilla bears a tubercle near its joint and 9 or 10 acute
teeth. The latter ones pointing outward. The mandible has 4 external tubercles, the foremost one pointing forward and an inner series of about 17 small
conical teeth of the characin type. These allow it to rip the scales from other species. It's an ideal choice for those wishing to keep a large shoal of a predatory species without possessing the massive amount of tank space needed for a shoal of piranha or similar. A tank full of these makes for a very colourful and active display.
Classification: Exodon paradoxus
Family: Characidae
Origin: South America. Exodons were originally discovered widespread throughout the Amazon basin and in the Orinoco basin within South America. It is widespread throughout the Brazilian Amazon basin and has also been recorded in the Rio Branco in Guyana.
Habitat: Usually found in parts of rivers flowing through savannah-like grassland. These biotopes are characterized by flowing waters over sandy substrates.
Size: In the wild Exodons are known to grow as big as 6". However, you will rarely see them larger then 3" in an aquarium. 4" is considered large in a home aquarium.
Minimum Tank Size: A 48" x 18" x 18" (120cm x 45cm x 45cm) - 225 litre/60 gallon tank is suggested to house a shoal of these fish. In anything smaller, however it really depends on how many you plan to stock.
Tank Setup: A biotope setup would consist of a substrate of sand with perhaps a few driftwood branches and roots added for effect.However, the fish are most at home when kept in a heavily planted tank. This kind of setup has the added benefit of containing plenty of refuge where individuals can go and seek some respite if they are being singled out for bullying. Filtration should be very efficient to cope with the fact that the species needs to be maintained in large groups.
This is an example of a natural biotope for this species:
Temperature: Exodons thrive in tropical temperatures of 78-82°F. However, they are pretty tolerant when it comes to temperatures as low as 70° and over 85°.
pH: Exodons can be naturally found at the range of pH 5.7 - 6.2 but can be found closer to ph 7 in home aquariums. This is a hardy species that is
easily acclimated.
Hardness: 0-20°dH
Description: Exodons are little fish with brilliant coloration. The caudal fin is yellow and the other fins are red to red tinting. They have two very large dark spots, one in the humeral area in front of the dorsal fin level and the other one covering the whole height of the caudal peduncle. They often have a slight blue to purple tint over their entire body with the females looking more yellow.
Diet Gut analyses of wild specimens have shown that the diet consists largely of insects and the scales of other fish. Thankfully, there's no need to
provide live fish in captivity as dead alternatives are readily accepted. Feed a varied diet comprised predominantly of meaty fare such as bloodworm,
chopped prawns, mussel, earthworms and lancefish. Most will even accept dried foods. Ensure that other tankmates are receiving enough food, as Exodon are
violent and greedy feeders. Stories have it that locals living in areas where the species is common place dirty pans and dishes into the water and the fish
perform a useful task by picking every scrap of food from them!
Compatibility These fish are found in the same areas inhabited by Fire Tetras (Hyphessobrycon amandae), Red-eyed Moenkhausia (M. oligalepis), two Corydoras species (Corydoras julii and C.nanus)and small sucking catfish (Otocinclus affinis). When kept in groups these will be fine to keep with Exodons. However, this is not a community fish in general and is best kept in a species setup. It will relentlessly attack any silver-coloured or shiny tankmates, stripping them of scales and fins very quickly. Some larger predatory species may not eve be safe. Scaleless and non-reflective fish are generally left alone. Success has been had keeping Exodon alongside various loaches, loricariids and some larger characins such as Anostomus. The situation will always be somewhat unpredictable though. It's best to add the Exodon last as they may see any new additions as food. With most predatory species they tend to bite
first and ask questions later.
A minimum of 8-10 individuals is usually recommended but buy as many as the tank can house. Generally, this is not a cheap fish at an average price of $7-8/ea. You can sometimes find them as low as $3-4 with a little luck. Be prepared to lighten your wallet a bit if you plan to keep Exodons. In a tank like the one described above a group of 25-50 would not be an unreasonable number. If kept in smaller groups, they tend to pick one another off until only a single fish remains. and a single Exodon will likely die of the stress from being alone. In large shoals, no individual can be targeted and it is usually only sick or unhealthy specimens that are killed. Occasional losses should still be expected. The interaction of a big group is fascinating to watch especially at feeding time.
You should buy the entire group at the same time since new additions are usually attacked. If you decide to add to your shoal after the initial group you should
add them in a group of 5 or more. A single introduced fish may be seen as food and killed before morning. It is also suggested that you do a water change prior to adding the new Exodons to the tank. This will help to distract the shoal.
Sexing: Mature males are slimmer than females. The females tend to be broader and wider and have slightly elongated dorsal and anal fin rays.
Breeding: Breeding has been achieved but on rare occasion. It's an egg scattering species. The best way to approach a breeding project is to set up a separate tank in which to spawn the fish. Something around 24" x 12" x 12" in size should be sufficient. This can be empty save for some clumps of fine-leaved plants to catch the eggs. Alternatively, cover the base of the tank with marbles or similar round stones. This should be big enough so that fish eggs can fall through it but small enough to prevent the adult fish from reaching them. Water should be soft and slightly acidic (pH 6.0-6.5, gH 1-5). Meanwhile, condition
the adults in a shoal in a separate tank as described above.
Once the fish are in good condition, select a pair and transfer them to the spawning tank. This can take a few tries as it is difficult to determine whether
or not a breedig pair has been established. Apparently, spawning can sometimes be initiated by performing a large 50%+ water change with slightly warmer
water than that in the tank. Remove the adults as soon as eggs are noticed since they will eat their spawn given the opportunity.
The eggs hatch in as soon as 48 hours and up to 3 days. There is little information available regarding the raising of the fry. It's likely that small live foods such as newly hatched brine shrimp will be accepted. Cannibalism will probably be rife so keep a close eye on the young as they grow and have several tanks ready to move differently sized fish into.
Other Notes: The genus Exodon is currently monotypic with this single species having uniquely designed teeth. The mouth of the Exodon is terminal and scarcely oblique; its pre-maxilla has an ascending process with 3 outer tusks and 6 inner acute. The maxilla bears a tubercle near its joint and 9 or 10 acute
teeth. The latter ones pointing outward. The mandible has 4 external tubercles, the foremost one pointing forward and an inner series of about 17 small
conical teeth of the characin type. These allow it to rip the scales from other species. It's an ideal choice for those wishing to keep a large shoal of a predatory species without possessing the massive amount of tank space needed for a shoal of piranha or similar. A tank full of these makes for a very colourful and active display.
