Hi there, I recently inherited a tank of livebearers, only to discover that it is brackish water. The instructions that came with it are that "a few tablespoons should be right for that tank" (80 litres) - can anyone give me more precise instructions please, and also how quickly can I change them back to fresh please?

One other question - the beautiful long-finned male molly has only one gill cover - I have never seen this before - gills exposed, but no bleeding or sign of recent damage - any clues please?

normally aquarium brackish water is formed at 1/2 concentration of instant ocean reccomendations...but as this can vary it would be best to ask the person who you acquired it from what the salt concentration was... As to how long it would take them to adapt to fw- I am not sure- most people would reccomnd a couple of days, however some people will say a couple of hours-and othere a couple of weeks- it all depends on who you ask

Thanks David for your comments, I was thinking a couple of months so a couple of weeks sounds ideal. In that case I will probably do weekly 20% water changes and just replace with fresh - that will bring it down slowly. I am not sure of the does you are recommending - what is the sea-water strength? I guess I am looking for a recommended number of teaspoons per litre of marine salt.

Mollies prefer a little salt in their water. Occasionally a fish is born without a gill covering and it is possible this is what has happened with your molly. I have seen fish like this before and they manage quite normally.

Hi Caryl, Thanks for your helpful comments. It did look so natural that I thought it must have been born that way. I am reassured now.

Cheers,

Sam