black fin shark...sick

Question
i have a black fin shark(catfish). least night when i got home from work he was fine swimming,eating good.....at 6:00 this morning he was on the bottom of the tank on his side.
i checked the water with my test kit, it was fine.( my other fish is fine.) i put ihim is a small tank by himself and put more salt in his water kept a check on the water,but about 12:00(noon) he died....he would try to swim but could not...the only fish that was in his tank were dianos, please help
thank you
Ellen

Answer
Hi Ellen,
By the symptoms you gave me I would think he had Swim Bladder Disease.  This is caused by overfeeding, and poor diet.  This causes constipation which leads to Swim Bladder Disease.  We should always feed our fish good food, and let them fast one day a week.  We should give them a pea on the day that they fast.  (You cook a frozen pea until it is well cooked, and tender.  Then, you remove the outer layer, cut in into small pieces, and feed them to your fish) This helps clean out their system.  Never add salt to the water when curing Swim Bladder.  You could not have know this, but it is best not to.  It might have been his time too, we don't always know their age when we buy them.
I'm sorry you lost your pet, but thankfully he did not suffer.
Hope this helps you understand a little more.
Lynda