Salt may be bad for us humans but it can be both a lifesaver and a useful material to have where fishkeeping's concerned.

All you've got to remember is to use sea-salt (rock salt) or cooking salt, rather than table salt which contains anti-clogging agents (magnesium etc) that should not be introduced ito the aquarium.

Use it as a prophylactic treatment, as a general 'pick me up' or a simple treatment for many parasitic diseases as follows:

COOKING SALT: A 2% solution = 20 grammes per litre of water.
                           Immerse fish for 8 hours.
                           Remove sooner if fish shows distress.
                           Raise temperature, supply aeration.

                           7 day treatment programme:
                           1st day 7gm of salt per litre.
                           2nd day drain 50% of the water and top up with fresh
                           water containing 11gm salt per litre.
                           3rd day drain 50% top up with fresh water with
                           13gm of salt perlitre.
                          4th day top up 50% fresh water with 17gm of salt
                           a litre, raise temperature and aerate.
                          Repeat after 7 days if necessary.


25 parts per thousand (ppt) salt solution (approximately 1 1/2 tablespoons of salt per litre) of water. This equates to around 1.018 specific gravity as measured with a hydrometer.

Brine Shrimp salt concentration details provided by courtesy of

Brine Shrimp Direct



Some species of fish inhabit estuarine waters which are partly saltwater, partly freshwater depending on tidal conditions. Monos, Scats, Gobies, Archerfish are typical examples as may be other species that inhabot coastal mangrove swamps. The Orange Chromide (one of Asia's few native cichlids) is another possible salt addict.

Some plants may not take too kindly to salt in the water although it is reported that Vallisneria and Sagittaria are salt-tolerant.

So what's 'brackish?'

The obvious answer is anything about halfway between fresh and full strength sea water, although the consensus is something less 'strong.'
Around 1.005 to 1.010 S.G is the usual agreed range as some freshwater fish may struggle with salinities at the higher level.

You can read more about THE BRACKISH WATER AQUARIUM here

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