Family Erythrinidae - Trahiras
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The information shared here is a collaborative effort, obtained from various web sources as well as information shared on MFK. Data shared is freely circulated and presented here in an attempt to provide better understanding of the Family Erythrinidae and to provide guidance of successfully maintaining these species in captivity.
Bibliography
http://www.fishbase.org/summary/FamilySummary.php?ID=103
http://www.monsterfishkeepers.com/forums/showthread.php?t=152940
Species summary
Species of this family occurs in South America. Body cylindrical. Gape reaching beyond anterior margin of orbit. Branchiostegal rays 5. Pectoral fin rays 9-14. Dorsal fin rays 8-15 and 3 vestigial rays. Dorsal fin origin anterior to anal fin and usually above pelvic fins. Anal fin rays 10-12. No adipose fin. Rounded caudal fin. Relatively large scales. Lateral line with 32-47 scales. Palatine teeth numerous. Some predaceous. Some capable of air-breathing and moving to other ponds by land. Nest-builders. About 1 m maximum length attained in Hoplias macrophthalmus of the Guianas.
16 individual species so far identified (fish base link);
Sp. Macrophthalminus discredited*
Origin and Habitat
Erythrinidae species are found in freshwater environments across South America ranging from Argentina to Guyana and Venezuela. Notable source locations include Rio Xingu, Rio Orinoco though their coverage is great.
A diverse and adaptable species, Erithrinidae are capable of inhabiting most fresh water environments from fast flowing streams and rivers to near stagnant pools and drainage ditches. Thanks to their adaptability, most Erythrinidae species will survive in a wide range of water conditions and temperatures though avoid extremes.
Habit
All Erythrinidae are predacious, though specifics diets vary from species to species. Some are dedicated Peiscovores, others feeding on insects and larvae through to small rodents and amphibians. Generally a solitary species, they are nocturnal ambush predators, choosing to rest in foliage during the day and hunt actively during the night. Sizes range from relatively small at just over 6 or 15cm through to over 100cm or 39.
General Aquaria information
Erythrinidae are predacious and as such, are generally unsuitable for the community aquaria. That said, examples do present themselves on a somewhat regular basis where specimens are kept in relative harmony with other large, robust species. However, it is widely accepted that this is generally down to the individual specimen rather than the species in general. Water chemistry is generally of secondary importance however water quality should be high. Due to their predacious nature, they are generally a messy eater, producing large quantities of waste.
When housing any Erythrinidae ensure the general rule of fish keeping is followed- 2x length = width, 4-6x length = length. Water depth is of secondary importance however overall footprint is most important. When housing large species, the above rules may seem unfeasible- Aimara for instance would require a tank of 18X6 so use common sense- you can never have a big enough aquarium.
Common traded species profile
Hoplias Malabaricus
Max size in captivity - 20"+
Locale Central to Northern South America
Minimum tank size - 120g 48" x 24" x 24"
Diet -piscivores - generally accept dead and live food
General information
The common Wolf fish is one of the more readily available members of the Wolf fish family. They are ambush predators, relying on their mottled coloration to camouflage themselves. They are very adaptive and can survive in varying water qualities.
The Malabaricus is a solitary species and incredibly aggressive towards all other fish regardless of size. It is generally a bad idea to try and mix a Common Wolf with any other fish. However, a number of people have tried with relative success to keep the Malabaricus with other fish of similar size or larger and even other Common wolves though success is rare. Breeding has been achieved in captivity, given enough space. The Male Malabaricus has a more slender body than the female.
In the aquarium, the Wolf should be provided with cover and relatively low lighting. Whilst PH and general water quality isn't important, ensure efficient filtration. The aquarium should have a secure fitting hood due to the Wolf being a notorious jumper.
Hoplerythrinus unitaeniatus
Max size in captivity - 16"
Locale - South America
Minimum tank size - 120g/ 48" x 24" x 24"
feeding - piscivores- readily accept dead due to voracious appetite
General info -
The Gold Wolf is one of the most unusual of the Wolf fish family. Unlike Hoplias Sp. or Ery. the Gold Wolf readily shoals with others of it's species. When others of its type are not available they happily shoal with characins of similar body shape (personal experience) such as Chalceus. Whilst small, they are fin nippers and generally very brave during feeding time.
They will co-habit with larger Characins and Cichlids, though ensure Cichlid species are not too aggressive or territorial. Whilst the Gold Wolf is not as aggressive as other wolf species, they are still capable of a fairly damaging bite. Catfish and Pleco's are also ideal choices.
Ensure plenty of open swimming space as these are among the most active of all Wolf Fish. Cover in not necessary due to the active nature of the species. As with most other Wolf variants, ensure a tight fitting lid due to their tendency to jump when gulping air.
...i would hate to hae to try and learn it as a second language as it changes every day...
