using salt?

[TankGirl]

Be careful as some species do not like salt!

 

[Moe36]

Thats why SW fish can't survive in FW; they hold onto too much water, and why FW can't survive in SW; they get rid of too much water...neither is able to remain in balance.

....but ive heard that pufferfish can live in both, FW, AND SW........????- is this corrct?

 

[Allivymar]

There are some fish set up to survive in both (mollys for example) although they prefer one or the other. There are others who are made for one environment and then change to deal with the other (think salmon).

But although mollys will survive in FW, they do better in brackish or SW. Salmon can only deal with FW or SW at certain times of their lives. The fish has to be a type already adapted by time and evolution to deal with those types of situations.

As for puffers, I'm not as familiar with them as I am with some other species, but if I'm correct, theres a couple thats start FW and require SW when they mature (kinda like salmon); there are others which are only SW or FW.

 

[TankGirl]

There are FW puffers, BW puffers and SW puffers. A lot of research must be done because they are often mislabeled and sold as FW, when they require brackish to thrive. I have dwarf (Malabar) puffers and they are completely fresh water fish. Most others that you see for sale are brackish. There have been many experiments done with the molly in full salt and brackish and fresh, and they can do it all. I do believe they prefer brackish, tho. I do not add salt to my tanks, BTW.