Fish at the surface of the water

Question
My fiance and I have had our fresh water tank for about 8 months.  We recently moved out of our apartment and unfortunaly, had to leave our tank behind for a few days.  We were able to feed our fish every 3 days.  To enable our fish to make the move, we had to empty about 1/2 of the water from our tank.  When they arrived at our new house, we added water and cleaned the tank.  All of the fish looked healthy at the time.  A day or so later, one angelfish started floating near the top of the tank.  We thought for sure he was dying, but its been almost a week and he's still moving around a bit.  We tested our water and it was high in nitrate and nitrite levels. We waited a day and did another water change.  After carefully observing our other fish, we noticed greenish scales on the tail of our rainbow shark.  We used an ich treatment last night, but I'm not sure if that was the right thing to do.  Any suggestions on what to do?  Do you know what disease(s) our fish are infested with?

Answer
Hello!

First of all, one water change rarely cures a bad case of nitrites, so you should carefully monitor the levels. These could easily be the cause of your troubles. I recommend adding a double dose of a denitrifier, such as Cycle. In fact, rainbow sharks don't have scales, but I believe the 'greenish scales' you are describing could be signs of deterioration due to high levels of nitrites. Check them again and start taking measures to rid your tank of them.

If its not nitrites causing the problems with your sharks tail, try a medicine to treat fin rot.

I hope this helps, good-luck!

From Stephanie