Care
The Glass Knifefish is widely distributed across South America, from the Rio Magdalena drainage east of the Andes in Colombia, to the La Plata River basin in eastern Argentina. It can be found in a variety of different biotopes due to the large area of distribution, but in general, it prefers deep ponds with aquatic substrates rich in plant debris, and is also found underneath islands of floating meadows in the floodplains. This nocturnal oddball is a micro-predator of insect larvae and small fish, and possesses a weakly discharging neurogenic electric organ and ampullary electro receptors that are distributed from head to tail. This means that the fish can not only sense electrical impulses, but can send them as well. These electrosensory systems are used mainly for electro-location, navigation, and communication, and are relatively weak as electric fish go, so pose no risk to the aquarist. This is a endearing fish which has an elongate, semi-transparent body. It moves in a graceful manner by undulating the long anal fin - which stretches the length of the belly, from just under the base of the pectoral fins to the caudal peduncle - and is capable of swimming forwards or backwards with ease. The Glass Knifefish is reasonably easy to keep, provided that some key requirements are met. Firstly, the male fish in particular grow very large, and, like other knifefish, cannot really bend - so a voluminous aquarium (at least 6ft long and a minimum 2.5ft wide) is a must. Secondly, the knifefish must be provided with a choice of shady hiding spots e.g. wide PVC tubes, rocky caves/overhangs (do ensure such structures are stable), large tangles of driftwood, and leaf litter (dried Indian Almond leaves are ideal, but will require periodical replacement). The lighting should not be too bright as these nocturnal fish are sensitive to intense illumination; if the tank must be brightly lit in some areas, provide plenty of broad leaved aquatic plants and floating species to help diffuse the light. Nonetheless, there absolutely must be areas of darkness within the tank that the fish can retreat to during the day as necessary. The substrate should consist of soft sand in order that the fish may grub about safely when searching for food, and so that the delicate anal fin does not become torn in any sharp gravel. Filtration should be efficient, but water movement not too vigorous. A consistent maintenance regime encompassing regular small partial water changes is important, as these fish are sensitive to elevated nitrate and sudden changes in water chemistry. Glass Knifefish are of a peaceful nature and are somewhat timid. They can be safely kept alongside other fish of similar size and temperament, and their gregarious nature means they should be kept in good sized groups of 6 or more. It is not recommended, however, that they are kept with any other knifefish species, any boisterous species, or any small species (which includes shrimp and snails) that would be considered a snack. Blue moon lighting, timed to come on just before the main lights switch off in the evening, is useful in observing your knifefish for a few hours under their preferred subdued illumination. Hopefully, if the tank is maintained appropriately and new fish are quarantined carefully before adding the main aquarium, the need for medications should not arise. However, if treatment is required, take much care as these fish are classed as 'scaleless' and are particularly sensitive to medications (always check with the manufacturer before using - some treatments are not safe, and others may need half dosing). Many aquarists also find that running a UV steriliser on the tank helps to eliminate pathogens and safeguards against the need for putting treatment in the water. This is a long-lived and fascinating species to look after, but this fish is quite a commitment so do ensure that all of its specific care requirements can be met before purchase. May also be seen on sale as the Green Knifefish.
Feeding
Glass Knifefish are micro-predators and should be offered a variety of small, meaty foods. Frozen fare could include bloodworm, white/black mosquito larvae, vitamin-enriched brineshrimp, Mysis shrimp etc, along with some dried foods such as slow sinking granules/pellets for carnivores.
Breeding
This species emits electrical signals during courtship. Spawning is said to take place during the early morning, with up to 200 adhesive eggs deposited on aquatic plants.
