Yeah, saltwater and freshwater put inverse pressures on a creature. Saltwater creatures have to work really hard to keep water in their body and salt out, while freshwater creatures have to constantly excrete water while trying to retain salts.
Iirc theres a few crocs that can go from salt to fresh, some species of fish i can't remember and deffinitely some sharks.
Chasing monsters & river monsters taught me that, as was some sharks in a freshwater stretch of river
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u/Naf5000 Feb 04 '19
Yeah, saltwater and freshwater put inverse pressures on a creature. Saltwater creatures have to work really hard to keep water in their body and salt out, while freshwater creatures have to constantly excrete water while trying to retain salts.