Sick Bala Shark

Question
Hi,
I have been reading your site for three days now and have not been able to find a problem and answer for what my bala seems to have.  I have a 55 gallon tank with one very large pleco and 2 bala sharks.  The balas are 8" and 7".  I have had the tank a little over a year.  I have been doing 25% water changes about every three weeks.  Ammonia and nitrites are 0, pH is about 7.5 normally, nitrates run right at 40ppm and I can't seem to ever get this down.  Three days ago, the pH was down to 6 (very acidic) and one of my balas was swimming on his side.  It has very extended gill coverings.  The skin covering its gills is hard and curled forward, exposing the red gills.  I can't see anything on the gills.  I moved him to a 10 gallon sick tank and started adding fresh water with a little salt in each gallon.  I added a heater and have the water up to about 80-82 degrees.  I have an airstone and two small filters running in the sick tank too.  I have been doing water changes for him every day for three days.  He does not seem to be getting any better.  The gill skin seems to be hard and not covering his gills entirely.  The gills are bright red.  He is now getting white slime on the areas where he is lying on his side.  I added a very little bit of Melafix to the water yesterday (less than a teaspoon).  I am very cautious when it comes to medicating any of my fish.  I have eight other tanks set up with various types of fish and everyone seems very healthy.  My bala has been hanging in there for three days now and I am just beside myself not knowing what else to do for him.  The other bala is perfectly normal and does not seem to have been affected by whatever is ailing the other one.  What else can I do for this poor fish?  Of course, I did an immediate water change on my 55 gal and all is well there.  Another note:  I am on well water.  I do not normally treat my water as there is no chlorine.  I age it for 24 hours before adding it to any tank and have had no problems before now.  Thank you for anything you can offer me.  Michele

Answer
Hi Michelle;

"Gill Curl" is usually related to high nitrates. All tanks really should have a 25% water change once a week, every week to help keep them under control. It will reduce nitrates even more if you vacuum the gravel every time. Big fish make big waste and that's what nitrates come from. Live plants absorb nitrates but there have to be a lot of them and some fish eat them faster than they can grow.

The 'laying over' problem with whitish slime is something else though, such as infection and possibly a swim bladder issue. Change water in his little isolation tank every day. Make sure the temperature of the new water is the same as the old water. I would replace 25% to 50% every time in the little tank. You could also use an antibiotic such as Erythromycin or Tetracycline. There are generic and brand-name products with one of those as main ingredients at fish stores. Or, you could go the natural route and use Melafix and/or Pimafix. Hopefully he will improve just with the water changes but it sounds pretty serious.

I have well water too with no additives and there really is no benefit to leaving the water to "age" overnight. It's kind of a pain in the neck anyway. I use mine right out of the tap with my spill-free water changing system (python brand). If my fish seem to be stressed for any reason or I have to perform a larger water change than usual I will add the new water more slowly and use a water conditioner just to help them out.

I hope he feels better soon...

At Your Service;
Chris Robbins