MollyFan1 said:
wataugachicken, I just added two today. They are called glass (ghost)cat fish. Will these be okay in brackish water?
If I remember right, glass cats are also scaleless fish and so I think salt would be a bad idea for them at least in higher amounts and over a long period of time. They are also not going to do well in a brightly lit tank so you are going to have to find a way to give them some 'shade' in the tank if you want to see them more often. They should really be kept in a group of five or more and even if you think that they look fine in just a pair, they really can get stressed out about not having enough friends, so to speak, and that is going to lead to other big problems down the road.
As for the brackish idea, you really do not need to keep mollies in brackish water at all and it will not hurt them in a very big way. They are actully a saltwater fish that has the ability to acclimate themselves to brackish water and then to freshwater. This is a rare case where it wont really matter to them at all, unlike fish like some puffers that need freshwater when they are young but will suffer if not put in brackish water as adults.
Besides, like was pointed out before, brackish water tanks are not just water with any old type of salt, they really need to have marine salts since they have the trace minerals/elements that regular salt does not have. So, you would incur higher costs from buying the right salt as well as having to keep a hydrometer or refractometer so that you can monitor the salinity. I believe that true brackish water has a salinity/spacific gravity of around 1.010, which is must closer to salt water than it is to freshwater.
I also wanted to point out that if you are going to dose aquarium salts (which many people feel is not needed and wrong in many ways, while others feel it is benificial) you need to only dose 1 tablespoon per every 5 gallons for regular cases but when there are scaleless fish in a tank, the dose has to max out at 1 tablespoon per 10 gallons. The one spoon per gallon, even if it is a teaspoon is too much and your scaleless fish like the cory cats and probrably the glass cats are going to be irritated.
Lastly, it is VERY important for you to realize two things...your tank is not cycled yet and so you shouldnt be putting any more fish into it until the ammonia and nitrite levels are always at 0 and the nitrates are as low as possible. The only good way to get rid of nitrates is through water changes, but the others will be 'transformed' into nitrates on their own. Ammonia and nitrites are very toxic to fish in low amounts so you need to focus on how well your fish are doing and base water changes on that for now. Mollies are tough enough to acclimate to saltwater but also to poor water parameters so that is why they can usually make it. The other fish probrably cannot take it that well.
The other thing you need to keep in mind is that salt is going to stay in the water all the time and the tank will get more and more salty as water evaporates and you add more water and more salt. The only way to get the salt out is to do a water change really so you should be careful not to over dose the tank with any type of salt until you have a way to measure the salinity.