I set up my 36 gallon freshwater tank on 1/20/07. I ran the tank with a Fluval cannister filter (using biomax and carbon as the media) for two days. Then I added 6 tetras as my starterfish to get the cycle going. Two weeks after I added the tetras (while monitoring water levels daily), I added 4 beautiful gouramis. My water levels before and after adding the gouramis were consistenyly: pH 6.5-6.8, no nitrate or nitrates spikes, temp at about 81. I treat the water with a conditioner and I add aquarium salt as well. I have beeen doing well with the water changes, I would say 15-20% every week.
After week 1 with the Gouramis the Nitrites did spike. I added an extra supply of the biomax filters to the bottom of my tank inside of a nylon bag.
Within 5 days the Nitrites converted and the Nitrates went up a bit. Now the levels are perfect.
My issue now is that yesterday I lost my Powder Blue Dwarf Gourami. It was horrible. I did not see any signs of illness or disease, only a change in his behavior. I noticed that he kept to himself in the corners of the tank and then as the day went on it was obvious he was struggling. He would work to get to the top of the tank and then fall to the bottom and wherever he landed he stayed for quite sometime. Then after a long day of struggling I lost him. :(
My other three fish that remain seem fine. The only thing I have noticed is that there is brown-red rusty coloted residue on some of my live plant leaves and some of the rock deco.
I guess what I am asking is, are there any preventive measures I can take to ensure I don't lose any of my other fish? Is the residue common? And about how long is it recommended to wait until I add additional fish?
Any help you can give will be greatly appreciated!