Acclimating saltwater mollies to freshwater?


New Member
So I’ve done a lot of googling, and everything I can find is all about acclimating freshwater mollies to salt, but I can’t find anything about the opposite.

I was setting up my saltwater aquarium and wanted some cheap cyclers for my tank, so I decided to go with mollies because I read that they could be used in saltwater too. I had my first algae bloom and got my inverts and all was good until my black molly decided to procreate a bunch of babies overnight. I knew she was pregnant (or I had some sort of idea), but I didn’t know when she was going to have her fry and I planned on putting her in a breeders box first so that I could catch all the babies.

Anyways, now I have nine fry in a diy breeders box and my tank unplugged because they keep on slipping down my sump box to their deaths. I was wondering if now that I have my aquarium established, I could move all the babies (and eventually the parents) to their own freshwater tank so that I can start getting some actual saltwater fish and not have to worry about the fry dying.

I vividly remember the guy at ***** saying that you could just throw the freshwater mollies into a saltwater tank and they will be fine (which I obviously was not going to do) but that when going from salt to fresh you have to be very careful. Has anyone ever attempted to bring saltwater mollies back to freshwater, and if so, is there a different procedure than just the slow acclimation process I used to put them in saltwater?



Well-Known Member
Kudos on you caring about the mollys. Mollys actually do best brackish, most live bearers are the same. Platys, swords, guppies, ect. So if you only want molly's in a tank just fill it up with water from a water change. Then add fw when you do a water change in that tank. Just keep the salt level around a 1.05-.07 and they will be fine


Well-Known Member
IME mollies do best in saltwater. In FW mine got a white cotonny fungus. Which cleared up in hours by adding some aquarium fw salt treatment.

my .02