About how much salt (grams per liter) for a fish to survive?

Question

i just bought a starfish and they gave us salt water but im obviously gonna need more.. so how much salt (grams per liter) would i need for the starfish to survive as if it were in its own seawater habitat?

Answer 1

Don't go by weight or a measurement (tablespoons, cups) per volume. Once you open the container, salt absorbs moisture from the atmosphere and compacts, so by using a weight, you're including the weight of the absorbed water and by using a volume, the salinity will increase over time as the salt compresses - both measurements will be "off".

The only accurate way to measure this is to use a hydrometer (http://www.thatpetplace.com/pet/prod/198151/product.web , http://www.thatpetplace.com/pet/prod/215123/product.web )or refractometer (more expensive, but more accurate: http://www.thatpetplace.com/pet/prod/199289/product.web ). Most people use the hydrometer which measures the specific gravity with a floating needle or a glass bulb that floats - as you add more salt, the needle floats higher in the water. For a starfish or any marine invertebrate, you want the specific gravity to be between 1.024 and 1.026.

And yes, you do need to use a marine salt mix, rather than aquarium salt because the marine salt contains all the elements found in natural seawater, not just NaCl.

Answer 2

can't you just buy like 25 litre tubs of cleaned salt water from the ocean, i did 4 my fish.

Answer 3

About 20 grams/1 liter. But you should probably get more just to be on the safe side!

Answer 4

well, first of all, you wouldn't use regular NaCl (table salt)
and it depends on what kind of starfish you have... you can but different "ocean" mixes at your local fish store... they have individual instructions on how much to use per gallon/liter

Answer 5

You need to get the proper aquarium salt from the store you brought the starfish from (you cannot just use regular table salt) and the label will tell you how much salt to add.