I have found 2 types of morrays that are often sold as freshwater morrays, the snowflake and the dragon (very cool they have a red and yellow head) morrays. I don't know if they are fw or brackish, but at the time I had a figure 8 puffer and put a SMALL amount of Doc Wellfish salt. This didn't harm anything in the water and was enough for my eel and figure 8. I really don't know if there are any true fw but I do know that they don't mind a little salt, not like bony eels (tiretrack, peacock, or fire...) But now that my experimenting with oddballs, I only have 2 tiretracks and 2 bichirs (Polypterid ornatipinnis and senegalus).