TIGER MORAY EEL (Gymnothorax Polyuranodon) A2405J

Gymnothorax polyuranodon is a shallow-water species, often dwelling in water with a depth of just ten feet (three meters) or less. It is found in shallow marine coastal waters, estuaries, river mouths, and for short distances upriver.

For years, it had been the accepted wisdom that the so-called "freshwater" moray eel was actually a marine species which, unlike most other morays, is able to tolerate water with lower salinity levels, and could even live in fresh water, but only for short periods of time. However, there is a growing body of evidence which suggests that Gymnothorax polyuranodon is a catadromous species of moray eel, in which the animal spends much of its life in freshwater but migrates to saltwater to spawn. The young eels are born in marine water, and then migrate into freshwater to live out most of its life. When the time comes to reproduce, the adult eels migrate back into the ocean to breed. Recently hatched eels, or elvers, are not seen in freshwater, and there is only one record of a G. polyuranodon elver found within saltwater. Juveniles are frequently encountered in brackish water, especially in mangroveforests, which they hide in for protection against larger fish. Adults are commonly found in freshwater, but it's possible that they are only short-term residents of freshwater environments.

In northeastern Australia, specimens of G. polyuranodon were observed over a period of three years in their natural habitat. The majority, nearly three-quarters of the observed specimens, preferred still pools or very slow-flowing water with lots of boulders for cover.

https://en.wikipedia.org/wiki/Gymnothorax_polyuranodon