Gymnothorax polyuranodon

[Stone Like Fish]

Hey guys,

I’ve seen conflicting info on these guys and there fresh vs brackish vs salt keeping.
What I’ve read is that they’re fresh but go to salt to spawn, like an Anguilla?
If you have or had one can you please let me know your experiences? Would be a species only tank. Also how long do they get? I’ve read everything from 2’ to 5’.

 

[Kilograms]

I've seen them in freshwater community tanks with other predators before and they do seem to thrive there. I had one myself that I grew from around 10"-16" until it disappeared one day. The largest I've seen personally was around 36" and almost as thick as my arm

 

[shern]

Hey guys,

I’ve seen conflicting info on these guys and there fresh vs brackish vs salt keeping.
What I’ve read is that they’re fresh but go to salt to spawn, like an Anguilla?
If you have or had one can you please let me know your experiences? Would be a species only tank. Also how long do they get? I’ve read everything from 2’ to 5’.

can confirm that they are 100% FW without forced alterations to environment, at least to current knowledge. It seems that some specimens in Sri Lanka/AU transition to SW once they reach adult sizes (likely following a similar process as most transitional eel species do for breeding), but it seems that this transformation doesn't occur unless prompted to so, unless you move a G. Poly into brackish/salt it will not undergo the change.

for ref i have grown my G. Polys from 8" to roughly 31". i keep a group of 5, and they are really personable.

one thing to look out for is their escaping abilities, make shore to keep all openings sealed and to weigh down lids.

As for max sizes, I'd say they top out around 40" and can sometimes reach a bit larger but it will vary on specimen and diet.

should be fine with a species-only tank.

 

[shern]