Hey ravenjinn! If I haven't already said so, welcome to the forum!
Well, I guess I would say that in general, almost all freshwater livestock can handle some amount of salt, but it would be the amount that is in contension I assume. I say that because, to be very technical about it, 'freshwater' is any water which has a salinity of less than 5 ppt...meaning that at any time, it would not be shocking to find some salt in any body of water.
Without considering the plants and the frogs (I know nothing of frogs and have an inadequate amount of understanding of plants to say anything with confidence), the general 'rule of thumb' would be:
Without Scaleless fish:
One tablespoon (three teaspoons) of salt per every
five gallons of actual water in the tank
With Scaleless fish:
One tablespoon (three teaspoons) of salt per every
ten gallons of actual water in the tank
The key things to remember here is that when I say 'salt', I mean sodium chloride such as table salt, kosher salt, aquarium salt...or salt as NOT being marine salt mixes, epsom salt, or any of the many other types of salt.
It is also important to note that our tanks do not really hold the same amount of water as they are 'rated' for. For example, my 55 gallon tank does not hold a true 55 gallon tank becuase the substrate, equipment, decorations, and fish themselves displace some of that potential 55 gallon volume. As a general guideline, I would 'guess' that my 55 gallon tank really holds about 45 to 50 gallons of water, but that would vary depening on how much/many of the above items are in your tank versus mine.
While I know that you may have already considered your stocking carefully, I have to say that IMHO, I would not be all that surprised to hear that you wind up having some problems with the combination of fish you have listed. While I honestly don't want to sound 'mean' or seem as though I know everything there is to know about every fish you have listed, in general, you have a mix of some very docile and/or passive fish in the same tank with other fish which tend to be agressive and/or territorial. For example, your amazon puffer and rainbow shark are both relatively territorial and can become agressive/problematic for other fish...particularily other bottom dwelling fish such as the cory cats and german blue ram cichlid that you also would like to keep with them. Granted, it is very true that once in a while we can find a fish which doesn't seem to 'act as advertised' or within the guidelines of its species profile, however, I bring this up because I feel that it is safer not to bank on this ideology or possibility since the most we can do otherwise is to cross our fingers and watch closely. Make sense?
Again, I apologize if I sound rude or like I am talking down on your ideas/plans as this is the least of my intentions. Instead, I would just rather bring these points up now before you have to find out the hard way, just like many of us have done.
Regarding the plants, I will see if I can get the attention of some other very helpful members of the forum since I know they can help you much much more than I ever could. Otherwise, if you would like, you could create a new thread in the
Freshwater Aquarium Plants section of this forum with the list of plants you would like to keep and I am sure you would get the right answer there.
