Black Mollies have white or silver on gills and body

Question
QUESTION: I am pretty new to the aquarium thing.  I have two black mollies and two guppies in a 15 gallon tank.  About a week ago, my mollies started getting some white on them.  The pet store thought that it was probably ick based on my description and recommended a liquid treatment.  I have been treating for a week now and it actually looks worse.  It looks like their gills are white when they open them and the spots have turned into white or silver patches.  I would appreciate any advice.  

Thanks.

ANSWER: Melanie,
First question is, did you cycle the tank before you added the fish? When it comes to mollies, they need brackish water. That means salt in the tank. It does sound like Ich and the safest and fastest way to get rid of it is heat and salt. Slowly turn their tank heater up to 84 degrees. Do this slowly to not shock the fish. In colder water it can take 6-8 weeks to get rid of Ich. In water between 84-85 it will take about 3 days. As you are upping the heater, add some aquarium salt at a ratio of 1 tbsp per 5 gallons of water. Make sure you dissolve the salt before you add it to the tank. The combination of heat and salt should have you Ich free in about 3-4 days. When you added the medication, did you remove the carbon from the filter? The carbon removes the medication from the water before it has a chance to work. Once the Ich is gone, you can start pulling the salt out by doing water changes. Remember, salt does not evaporate and if too much is added to the tank, it can harm the fish. Since it does not evaporate, you will have to remove it by doing daily 25% water changes for 4-5 days.

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QUESTION: Sorry,I am not sure what you mean by cycle the tank.  We originally had a 3 gallon tank with 3 glow fish.  We had it for about 1 month. I cleaned the tank and replaced about 75% of the water. (I now know this wasnt a good idea). I must have cracked something and the next day it began rapidly leaking. I moved them temporarily to a 2 gallon fish carrier.  I kept them in the remaining water from their tank. This was on a Saturday.  On that same day, I purchased the 15 gallon tank.  I used the remaining water from the previous tank and added filtered water with conditioner.  I waited about 20 hours before moving the fish into the 15 gal. tank.  I also added two mollies at that time.  At the advise of the pet store, I ran the new larger filter, and also ran the old filter to add bio to the new tank.  I reused the rocks, plants, etc.  He advised that I use both filters for about 1 month.  One of the glow fish did not make it and died that same day.  About 1 week later, the 2 additional glow fish died. I thought that it was probably the stress of the cleaning and the move.
The following Saturday, I bought and added a biological filtration booster and added it to the tank.  I also added 2 guppies and a frog.  The frog got stuck in the filter a few days later and didnt make it.
On the 3rd Saturday, I added more biological filtration booster per the instructions and noticed the white spots on the mollies.  I began using ich treatment twice/day per the instructions and removed the carbon filter from the larger and newer filter.  I did not remove it from the smaller and old filter because it was over 7 weeks old and I was told that the carbon was inactive and there was not need to remove.  I did not turn up the heat or add salt.  I have now turned up the heat and will add salt tomorrow when I make my weekly trip to the store.  
The instructions on the ich treatment bottle say that 25% of the water should be replaced after treatment, but I treat 2x per day and I was concerned about the bio matter in the water. I have kept the filter out for 6 days, but have now added it back because the water is starting to look the color of the ich treatment.  I will take it back out and continue treating with heat up and salt added.  I will also replace 25% of water per your advice.  If this info changes your opinion as to what I should do, please let me know.  

Thank you so much for your advice!!

ANSWER: Melanie,
All new tanks, that will have a filter, need to be cycled before the fish are added. This process takes 6 weeks and sometimes longer. When you set up a tank with a filter there are two bacteria blooms that happen during the cycle process. The first is the bad stuff that can kill the fish. The second is the one that both the filter and the fish need to be healthy. As for using the biological filtration booster, I would stop using it since the only thing it does is add things to the water that the fish do not need. All carbon filters need to be removed from the tank regardless as to how long they have been in the tank. I would just continue to treat with heat and salt. I would also not add any more fish until the tank has been completely cycled. If you need help with that, let me know.

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QUESTION: Thank you so much for your continued help.  I have turned up the heat to 82, added salt at 1 rounded tablespoon per 5 gallons, have continued ich treatment and have been replacing the water 25% per day with conditioned water.  I am sad to say,however, that I don't think my male molly will make it through the night.  I have put him in a smaller tank with water from the larger tank because the female molly is making him miserable.  That leaves me with a male and female guppy and a female molly. I also now have 8 guppy fry. Is there a possibilty that this isnt ich and that I should be treating for something else?  I would really hate to lose all of the other fish in the tank.

Thank you so much!
Melanie

Answer
Melanie,
If your fish look like they have been sprinkled with salt, then it is most likely Ich. You can try a salt bath with the male. Dissolve 1 teaspoon in one gallon of water. Once dissolved, let the male swim around for a few minutes, not more than 10 minutes, and then put him back in his smaller tank. Do this twice a day, but DO NOT use the salt water twice. Make it fresh every time. This gives him a larger dose of salt and might help him out. The guppy fry, if in the same tank, might not be able to handle the Ich medication. Keep watch over them, and remove them if you see them starting to have any kind of problems.