Henry & Tammy's Place/Water Requirements

Freshwater To Brackish and Beyond

The Water

Since this subject evolves around fish I guess its best to start with an understanding of the differences between Fresh and Saltwater and realize that Brackish fits somewhere cozy in between and can stradle both to some degree. Same with fish.

Freshwater: Water that does not contain salt, or is not saline. Has specific gravity of 1.00 (0% salinity)
Brackish: Water that is neither fresh nor saltwater, but is somewhere in between, although the salinity leans towards freshwater. In nature this occurs at the mouths of rivers and swamps near the sea. Some fish live in salt water but are spawned in brackish or fresh water and vice versa. Has specific gravity of 1.00 to 1.013 ( up to 1.5% salinity)
Saltwater: Water which is more dense than Freshwater and contains salts as found in the open sea. Along with sodium chloride it contains calcium carbonate and bicarbonate, various metal salts, and small amounts of phosphates, sulphates and nitrates. Saltwater reaches specific gravity from 1.013 to 1.03 (1.5% to 4% salinity)
Specific Gravity- The measurement used in marine systems to describe the salt content of water.
Salinity- The measurement of dissolved salts in the aquarium water. Usually given as the number of grams of dissolved salts in 1,000 gallons of seawater.

The Fish
The ultimate goal here is to have your fish be able to achieve and maintain the proper balance of salt and water in the body. This occurs differently between Fresh and Saltwater fish. Freshwater fish have a higher concentration of internal salt content than the surrounding water while Saltwater fish have the opposite, a lower internal salt content than the surrounding water so it goes to show that Brackish again, falls in between.
The process by which achieving this balance of salt to water ratio in the body of fish is known as osmosis. Osmosis is the phenomenon of water flow through a semi permeable membrane (the gills of the fish) and blocks the transport of salts or other solutes. When two water (or other solvent) volumes are separated by a semi permeable membrane, water will flow from the side of low solute concentration, to the side of high solute concentration. The solute molecules generate osmotic pressure on all the solution boundaries, in this case certain internal organs along with the gill membrane. To explain this more simply, freshwater fish as stated, have a higher concentration of internal salts so they equalize the pressure of salt to surrounding water by more urine output. Saltwater, the exact opposite, less urine output. Again, brackish water fish fall somewhere in between. Oh my.. I'm happy that explanation is over with!!! *lol*
This leads us to which fish are suitable for which types of water. I am going to stick to Freshwater versus Brackish since at this time that is where my interests lie. I also will say that I don't necessarilly agree with what is listed as intolerant because Henry and I have kept some of these fish listed in tanks with some degree of salinity without any problems. Because I would not want to risk *your* fish I am airing on the side of caution and basing the chart on what information I have been able to find and substantiate in more than one place on the internet. I will identify which fish we have kept with a degree of salinity, albeit low, with an asterick(*). The different species of Puffers seem to be very broad with what they require. In each section below I will list the various Puffers where they fit and under the words 'Various Puffers' in bold. Other than that I am going to stick to generalities. (For good reason)

Freshwater Salt Intolerant Specific Gravity 1.000	Freshwater Low Salt Tolerance Specific Gravity 1.005	Freshwater Moderate Salt Tolerance Specific Gravity 1.015	Brackish High Salt Tolerance Specific Gravity 1.025
Tetra's* Goldfish Minnows Loaches* Rasboras* Danios* Dwarf Catfishes Corydoras* Rainbowfishes*	Soft water Cichlid Angelfish Soft water Cichlid Discus Most Labyrinth Loricariidae Sucking Catfishes Various Puffers Red-eyed Figure Eight Congo Green Spotted SouthEast Asian Freshwater African Spotted South American Nile Twin Spot Giant Freshwater	Cichlids Livebearers Killifish Central American Cichlamosa Kribensis Sleeper Gobies Spiny Eels Shark Catfishes Bumblebee Gobies Halfbeaks Various Puffers Common Spotted Milk Spotted	Malayan Angel Fingerfish Archerfishes Targetfish Scats and Argusfishes Aspredinidae Catfish Family Ariidae Catfish Family Plotosidae Catfish Family Batfish Lionfish Mangrove Jack (Snapper) Humbugs (Damsel) Sergeant Majors (Damsel) Various Puffers Dog Faced Northern Globefish

The Brackish Water Aquarium FAQ- Compiled by Neale Monks Ph.D

There is much more to Brackish Water Aquariums than just the level of salinity present. As important is paying attention to the temperature, hardness and pH of the water. On Dr Monks site all of these issues are explained better than I could ever dream to so I'm not even going to try. *lol*