Disease Prevention

[ChrisSimpson]

I have a 44 gal freshwater tank in which I just had a female swordtail
succomb to some sort of disease. About a week ago I noticed her underbelly to be kind of swollen and with a white coloring. Over the past 3-4 days, her skin turned dull, she became inactive and isolated herself from everyone else. During the end stage she'd developed a white coating on top of her body and two white-yellow streaks on her tail fin, as well as a gold-colored spot on her face just below her eye. Does that sound like velvet disease? She expired just this morning, and at this point everyone else looks and acts just fine. Before I go shooting any chemicals into the tank, are there some good preventive measures I can take, such as a small water change, adding some element of aquarium salt, raising temperature, etc.? I do 15% water changes weekky, maintain a 75-degree temperature in the tank, and my chemistry and water quality appear okay according to daily litmus testing. Any advice is greatly appreciated. Thanks all. - CS

 

[BillD]

Your wtaer change regimen may not be enough. I can't comment on the possibility of velvet, as I have never actually seen it. When mysterious deaths occur, I do an immediate water change of 50%. Actually, all my water changes are 50% or more. Litmus testing will not indicate water quality. If the tank seems to be doing okay at 15%, an occasional larger change would be beneficial. Toxins that noone tests for build up over time,and a lrger change will reduce them, more. In your case it would seem that there is definitely a disease organism in the tank, so I would do several wtaer changes over the next couple of days to try and reduce the level of pathogens in the tank. Perhaps a thorough gravel vac would be in order too. Good luck.