True Freshwater Eels?

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masone said:
Gymnothorax polyuranodon is a true freshwater moray. I know Brendan Ebner and two of the other guys who research them. Brendan has about 9 of them in a few full fresh tanks. Link to first research paper, they will be doing otolith banding to see how long the morays are in brackish environments as young and whether they return to spawn etc. http://onlinelibrary.wiley.com/doi/10.1111/j.1095-8649.2011.02987.x/abstract
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Just because its in Freshwater doesn't make it so. There are no true freshwater Morays, wish it wasn't so but it is.
 
Chrisplosion said:
Just because its in Freshwater doesn't make it so. There are no true freshwater Morays, wish it wasn't so but it is.
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Maybe you could pass on your wisdom to Ebner, Theusen, Allen, Pusey et al
Not having a go at you but this being a fishkeeping forum your antecedants and expertise on the subject being ?
 
There are no fresh water true eels (anguilliformes), many live there lives in fresh water but go to sea to breed and eventually die and the young come back to rivers lakes etc to live out their lives eg american eel. So they cannot be classed as truly freshwater although they are fine living in freshwater lol, they are "Catadromous". All the moray types are at least brackish to full marine. Spiney eels are elongated fish not true eels same with electric eels and swamp eels.
 
New Zealand Longfin Eels were on that show River Monsters and, they migrate to SW to breed!
 
Interesting all the people who say there are no true fresh eels or morays. I'm sure the scientists here who are studying G. polyuranodon would appreciate knowing they have been duped and have spent the last few years wasting their time and funding. Reading the scientific literature on this species and talking to the scientists as opposed to relying on internet fuddle would suggest that G. polyuranodon is fresh to brackish at the very least. What classifies as true freshwater? I would say any fish that can live in full fresh is true freshwater. Saying they aren't because they breed in marine/brackish is beside the point unless you want to breed them. It's like saying barramundi and a plethora of other fish are not freshwater because they enter marine/brackish environments to spawn.
 
The subject of freshwater eels is a touchy one considering that most hobbyists don't bother to differentiate between the true eels & the eel-like fishes.

True eels:
Of the true eels, the Order Anguilliformes, there are only two genera that contain at least one species that spend most of their lives in freshwater, the Genus Anguilla & the Genus Gymnothorax.

All of the species in Anguilla are catadromous, e.g. fishes which spend most of their lives in freshwater and migrate to the sea to breed, which means that they're freshwater eels. Examples of this genera include the New Zealand longfin eel (Anguilla dieffenbachii) and the American eel (Anguilla rostrata).

Of the numerous species in Gymnothorax, only some populations of the freshwater moray eel (Gymnothorax polyuranodon) can be considered to be freshwater eels. Not all populations of this particular species are freshwater, but that doesn't change the fact that some populations have been found to spend their entire lives and even breed within rivers & streams in Australia (probably in other places as well) despite the fact that the could migrate to the ocean if desired.
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Eel-like fishes:
There are the eel-like fishes of the Order Synbranchiformes (swamp eels, earthworm eels, & spiny eels), and those fishes are all freshwater "eels" to my knowledge. Another eel-like fish is the electric eel (Electrophorus electricus), and it too is a freshwater "eel" that is in the same order as the South American knifefishes.
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masone said:
Interesting all the people who say there are no true fresh eels or morays. I'm sure the scientists here who are studying G. polyuranodon would appreciate knowing they have been duped and have spent the last few years wasting their time and funding. Reading the scientific literature on this species and talking to the scientists as opposed to relying on internet fuddle would suggest that G. polyuranodon is fresh to brackish at the very least. What classifies as true freshwater? I would say any fish that can live in full fresh is true freshwater. Saying they aren't because they breed in marine/brackish is beside the point unless you want to breed them. It's like saying barramundi and a plethora of other fish are not freshwater because they enter marine/brackish environments to spawn.
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Then by all means link to evidence that back up your claim, I'm so eager that someone can disprove my decades of knowledge on this topic.
 
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