Can you get any freshwater fish to live in salt or just Mollies? I was looking at those Black Tip sharks they only get 6" at most. This would be the only way I could get a shark.
I heard you can change some FW into backrish water, but im not to sure, mb if u done it by drip or somthing, i really dont know. but some1 else might have tryed.
i suggest you do some more extencive research about brackish species to find out which migrate to full sw as adults.this is the deciding factor of what species can be acclimated to full sw.sailfin mollies breed and live in brackish water as juveniles some even in more fresh water in nature but as adults move to the more open waters of the sea.not all brackish species will do this.
The Columbian shark (Hexanematichthys seemanni, if thats what your talking about ) is a catfish that can grow up to 13in. They must be acclimated to full SW conditions as they mature or they die.