Finn MIGHT have fin rot

Question
I just got my Betta, Finn, yesterday. I am pretty sure he has Fin rot. He came looking this way when i got him at the pet store(fins all ragged little clear black rim around the edges)Doesn't fin rot come from bad water? I have fairly decent water so i was hoping it would clear up. What kind of treatment Should i use? Or should i wait and see if it clears up? i have heard that it can be fatal and in Just one day i have gotten so close to him
thank you

Answer
Hi!
Fin, and Tail rot comes from poor water conditions.  A betta should be in a 5 gallon heated tank.  When bringing him home from the pet store, "we all know the sarcastic little cups that they come in" we must put the Betta in water similar in temperature.  Then we bring the temperature up with a heater, very very slowly.  We bring the temperature up one degree every day, or second day.  Bringing up the temperature too quickly would be deadly.  The Betta is a tropical fish, and should be in 80-82 degree water.  He should also have a silk plant so that he can rest on the leaves, and a small toy he can go through.  Adding one teaspoon of diluted aquarium salt will help the betta with Stress, and Parasites.  The betta's water must be changed completely, always using a good water conditioner such as "Stress Coat" every 6-7 days in a five gallon tank.
Fin, and tail rot quickly eat away at a fish.    
"Kordon Ick Attack"  would be a good medication to use.  This medication will help with fungus, and parasites.  It is like having 4 medications in one bottle.   It will not harm your betta since it is organic.  I would give this medication a try.  Never use "melafix" for a betta.  This medication is too strong for them.
I would also like to mention that betta's need varied diets.  Betta pellets, betta flakes, plankton flakes, Daphnia, (Daphnia is very important as it helps the betta with his digestive system,) Bloodworms, now, and then as a treat, Glassworms, Mealworms, and Frozen Brine Shrimp.  The more you vary, the healthier he will be.  Clean water, and good food, go a long way in preventing disease.
He should also have one frozen cooked pea a week, with the outer layer removed.  Cut the pea into bite size pieces, and feed the pieces to your betta one at a time, making sure he eats them, and that they do not fall to the bottom of the tank.  On the day you choose to feed him the pea, feed him nothing else.  This is so he can clean out his system, and avoid Swim Bladder Disease to which the betta is prone.
Feed him small meals, never big meals 2-3 times a day.  Two pellets, or two flakes is enough for one meal.  We must always remember that the betta's tummy is the size of his eye, so we must be careful when feeding them.
We do get attached to this little clever fish very quickly.  They are so intelligent!
I hope he will recover quickly.  Please keep me posted on how he is doing.
Lynda