Freshwater Aquarium problems

Question
Hi,
I'm sorry for asking so many questions, but I just can't seem to not have problems. I recently wrote to you about what you thought was brown algae. You advised me to feed the mollies vegetables/green algae. I had not given that to them yet, so there was no change in diet. Then when i woke up this morning, i noticed there appeared to be a few spots of ich on 2 of the mollies. So, I added 10 tsp. of salt to the water, and the amount directed on the bottle (1 tsp.) of Rid Ich. These were the treatment methods I had used before, so thats what i did since i only had about 5 minutes. When I came home, the signs of ich seemed to be gone, and the fish fine. Then about 20 minutes after that I went to feed them, and one of the mollies was laid on its side on the gravel, and appeared dead. Looking closer, it is still breathing ( i 1st found it about 20 min. ago now) but it appears like it will certainly die. I don't know whats wrong though. My two black mollies (its one of them) had been somewhat agressive, nipping at each other, could it have been hurt? Or maybe it was the rid ich? Also, the heater had been acting a little funny and the temp. had gone suddenly up to about 82F then dropped down to about 75F in one day. Could the stress have killed it? (That was yesterday) Can you please help me, I would really appreciate it. Also, should i treat for ich, even though it seems to be gone, and maybe wasn't ich after all? Also, another one of the mollies has been gulping air at the top since i got it. The other mollie and the guppies i have seem fine. Also, in cast you don't remember, I got three mollies a week ago, and have had 2 guppies for 2 months. Its a ten gallon tank. Thank you for your help. (And sorry it's so long.)
-Alina C.  

Answer
Hi Alina;

The mollies probably just had some little bubbles on their fins. It happens sometimes. Ich spots take at least 3 or 4 days to visually disappear. The temperature change probably did stress them out. Watch for ick in the next few days. It attacks in times of stress.

It would be good to make another 25% water change. With so many fish in there your tank will need a 25% change once a week. Mollies get to be about 3 to 5 inches long depending on the type, so the tank is going to be full once they get to be adults. Mollies also need very clean water to stay healthy.

Gasping air at the top can often indicate a water quality problem, but could also be a gill disease. If the others don't seem affected, maybe the gasping fish had gill damage before you got him. Maybe add extra aeration with an airstone hooked to an air pump. It may perk everyone up a bit.  

I hope everything goes okay.....

At Your Service;
Chris Robbins