brackish water

I'm thinking of using salt, sodium cloride, potasium cloride and calcium cloride to see if i can keep certian salt or brackish fish with freshwater fish. I am thinking of a minimal amount of sodium cloride and using mostly calcium cloride and seeing if I can keep hermit crabs in a tank with fresh water fish. Has anyone else ever tried this?

Michael

Edited by Moontanman, 28 February 2008 - 11:34 PM.

I can't help you with the hermit crabs.
I have been mixing brackish and freshwater fish together for years. Basically, I acclimate the brackish fish to my tap water which is reasonably hard but not too too hard. I do not add any salt or minerals at all.
Currently I have 90 gal planted tank with no salt or anything else added. The fish I have in it are flag fish, sailfin mollies and rainwater killies. The mollies and killies were collected in full strength seawater. All are thriving, growing, in full color and breeding regularly. In fact, the last of my original wild caught mollies died recently, apparently from old age, and all the ones in my tank now are second and third generation captive bred.
In the past I have also kept 3, 4 and 9 spine sticklebacks, all collected in full strength or nearly full strength seawater, in my tap water without any added salt or minerals.
I never added salt when I kept rift lake cichlids either.
I have no clue how hard my water is or what minerals are present. I've never had it tested and don't have test kits.
Your milage may vary depending on your water parameters. If you think it may have good mineral hardness, you might try some of the hardier brackish fish without any added salt. Just acclimate them very slow with a drip slow enough that it takes two days to fill a five gallon bucket.

Something that I've never done but is possible is to add some of the more salt tolerant freshwater fish to a brackish tank. Examples of freshwater fish I have encountered while fishing in brackish estuaries include largemouth and smallmouth bass and white catfish. I'm sure there are others.

The Japanese have done a few things like this (keeping Discus with Clownfish), but it takes some crazy technology. One guy was posting on Reef Central about 4 years ago....aside from the mass flame war that ensued, and the thousands of dollars of equipment, it was really cool. I can't say that I would recommend something like this. Some fish are suited to fresh and some marine. You'll end up torturing the fish if you don't know what you're doing.