Hmmm, that would be interesting. They might be able to live in high end brackish (SG 1.018+). I've found these "mother in law fish" as they call them in the fishing world way up in the rivers in the glades, however idk if they spend any significant time there. Also, that water is so close to the ocean and has such a large tidal influence that it may be closer to full marine anyways.....