dick tropical fish silver lyretail molly and now guppy

Question
I have a 20 gallon tank, with some guppies(4), platies(3)a pleco and 2 silver lyretail Mollies.  the female just had babies about 4 days ago, and the male just died 2 days ago. all the other fish have been in the tank now for a long time (year).  the Mollies were added about 2 weeks ago.



the symptom are that they hang at the top vertically, it almost seems as if their tails were paralyzed--like they couldn't move it.  the flutter only their front fins.  they don't seem to have the pine cone look, their appetite has become poor, and initially their "mobility" seems to get worse after eating but it's hard to tell since they have little interest in food.  The female is acting this way now too.  i think she is doomed but I'd really like to save her.  I add 3 TBSP salt to my water changes (about3/week) i stepped up the water changes when he started showing signs and added 2 TSP of pima fix--he got to the point that he would "stick" to the filter tube.  I cant tell if its ich since it's hard to see white spots on a white fish..

my one female guppy seems to have the same symptom.  her tail "flops"downwards,and she doesnt seem to use it to get about.  both hover at the surface,
i feed an assorment--flakes, frozen brinke shrimp, frozen blood worms, freeze dried bloodworms, and hikari guppyblls (very small)and the hikari small mouthed pellets for the tetras
I did a water change last night (not quite 50%--usually do about 25-30%) and added 2 TBSP of salt, and turned up the heater from about 77 to 80
Help?

Answer
Hey Janet,

Get your salinity tested, it sounds like you might be over doing it just a touch. Adjust the heater to keep it between 76 and 78, 80 starts to suck out needed O2 from the water. Drop the Pima fix, because it's completely worthless :) and get yourself some tetracycline or coppersafe. If you suspect ich, i'd suggest coppersafe. Maradel makes good products, and carries both medications. They come with a nice diagnostics guide too, so it'd be in your best interest to pick up either of the two, and read the guide as well. It'll help out a lot in pin pointing the exacts. While treating, use some Am-Quel as well, as i suspect the new additions, plus the birthing, and perhaps over feeding could be leading you to ammonia problems. Test the water and the salinity, and make adjustments as needed. Good luck and best wishes!