These are sometimes sold as speckled longfin eels, they are a bit more slender than the mottled eels but get at least as long with confirmed specimens at 76", there have been uncomfirmed reports of indivuals in Tasmania supposedly 8' long. they are mainly nocturnal and active predators. They are not as commonly sold as the marmotus but if you can find them are easy to keep if you have a very secure tank (they are determined escape artists. They will not sexually mature unless kept in salt water but this is a good thing as they age rapidly once mature, in fresh water they live as long as 40 years. They are found wild in slow moving water ranging from mountain fresh to full salt and at temperatures from mid 40s to mid 80s faranhiet. They are also tolerant of low O2 levels. Although not a shoaling fish they are tolerant of other eels that are to large to eat.