I've heard there are true and false knifefish? Is that really a thing? If so, what are the differences? Also are clown featherback and aba aba true or false knifefish?
What are true and fast knifefish?
- Thread starter Pyluper
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'Knife-fish' is a general term for any and all freshwater teleost fishes with a continuous undulating anal fin, with a reduced/vestigial caudal, no ventrals, etc. Gymnarchus niloticus is unique in that it has no caudal/anal/pelvic, just pectoral and dorsal. But is still called a knife-fish because of the main undulating dorsal-fin they employ for somewhat similar means of movement.
The true knife-fishes are the electric Latin American spp. of the order Gymnotiformes, that can be easily differentiated from other 'knife-fishes' besides Xenomystus by the complete absence of a dorsal-fin. They are capable of controlled electric sinusoidal wave-output for communication and navigation, and in the case of Electrophorus spp. hunting as well.
A false knife-fish- Gymnarchus niloticus- aba-aba- is able to employ weak electronavigation due to them being fairly closely related to the African elephant-nose fishes, Mormyridae. But they are quite morphologically unique and easy to identify anyhow.
The false knife-fishes are the Afro-Asian spp. of the Notopteridae (and Gymnarchus, but again that is moreso an odd exception). This includes the African Papyrocranus and Xenomystus; as well as Asian Notopterus and Chitala. They are, for the most part, incapable of electricity output on a level anywhere remotely close to the true knife-fishes, have a fully-functional dorsal fin (besides Xenomystus, which is easy to identify apart from all others by head/eye-shape alone), employ slightly different means of swimming, have completely different overall morphologies, etc.
Clown knifefish- Chitala ornata- and Aba-aba- G. niloticus- are both what would be called 'false knife-fish'.
Here in Panama, we have 5 species, of so called knife fish.
One species has a subterminal mouth (considered toothless), and the other terminal.
I caught this one the other day, in a fast flowing stream barely 20 ft wide, it may be Bracyhypopomus occidentalis (Regan 1914)
One species has a subterminal mouth (considered toothless), and the other terminal.
I caught this one the other day, in a fast flowing stream barely 20 ft wide, it may be Bracyhypopomus occidentalis (Regan 1914)
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Knifefish is a common name given to several genise of fish found in SA/CA, SE Asia and Africa. They share a common feature of having undulating finnage for locomotion allowing them to swim like a knife without wiggling the tail. I've never heard of true and false knifefish, perhaps referring to electrical and non-electrical for true and false. The Asian species have big eyes and are non-electrical, and the rest are electrical with tiny nearly blind eyes. The powerful electric eel is not an eel, but a strongly electrical knifefish.
Not Brachyhypopomus, I have kept and tried to breed a few sp. and their morphology is rather different. Jaw morphology varies a bit within various genera, I do not like using it as a sole diagnostic characteristic for genus ID.
Yours would be a lovely Sternopygus sp., the size alone is far greater than any Brachyhypopomus as seen in the video.
Hope yours continues to do well, they are very interesting fishes and a fun addition to most suitable tanks.