Betta tail turning brown

Question
QUESTION: I just got a Betta 3 days ago.  Was Beautiful blue.  Put into 5 gal hexagon aquarium with filter and light.  He was really enjoying and spreading fins.  Now he is pretty much on bottom and if not is zipping around the tank, fins pretty much pulled in.  It is not much but progressing quickly so I am worried about him.

ANSWER: Alright... I may need a bit more info from you, but I'll see what I can do with the information provided.  Once he gets better from this, you may want to include these questions if he has any further problems...

Fin clamping, when they pull their fins in, is a common symptom.  With just that problem displayed, it could be any numerous things, so
you must link it to other symptoms to narrow down the problem.

In the title you said his fins are turning brown... with a fungus?  If there's a fungus, then I would go to the pet store, and ask the clerk to suggest a fungicide.  If it's a black-brown colour, with little to no fungus, but quickly deteriorating the fins, that could be fin rot.  Again, ask a pet store clerk for their recommended product in your area.

With the symptoms of a bloated body, with or without scales protruding, it could be dropsy or bloat.  This is treated with epsom salts(1/8 tsp per 5g), and fasting for three days, then feeding a pea.

If your fish also has defined white spots, it would be ich.  Easy to treat, there are various treatments.

If your fish seems to have a dusting over his body of whitish or off-white(sometimes even golden) powder, that would be Velvet.  A broad spectrum antibiotic is an effective treatment.

It could be that the tank is too cold - bettas like warmer water, I keep most of mine at 78f, but there are some sulkers who like it as high as 82f.

He may be distressed - can he constantly see another betta?  Can he constantly see a female?  Is there a cat or dog that could be upsetting him?  Is he alone in the tank?  Bettas, while marketed as hardy, are actually very succeptable to stress and emotional problems.  He could be sulking because there's too much or too little activity.  This can be accompanied by low appetite, but doesn't have to be.

If you need more help than this, please include in your reply the following information :
1.  What food types and how often he is fed.
2.  Light schedule(ie 12h on 12h off)
3.  Any tank mates
4.  Tank temperature
5.  Water maintenance - additives, change schedule, change ratio.
6.  Detailed description(or photo links!) to the fish and problems you've seen

Hopefully you can match any other symptoms to your fish, but if not, please feel free to contact me again, and I would be happy to help you further.

---------- FOLLOW-UP ----------

QUESTION:
Thanks for the help!!! apprciate it.
actually, I changed the water and turned off the light.  PETCO told me no to the light that came with the Hex Tank---freakin him out. he seems a bit better already.  they also said I was feeding too much and maybe the brownish look to tail is sulpher burn so not to feed but maybe 2-3 nuggets 2-3 week thats it. I was feeding about 5 nuggets 2 times a day.
The tail is worse even from lastevenging AND this morning. About 1/2 is goldish brown. No bloat. No fungus. No white spots etc.  I dont have a heater but tank is staying about 76 degrees.
I just feel soooo bad....he may be just a fish but I took him and now he is sick.  :(

Answer
"its me again, the one with the new betta with tail turning golden/brown color..no fungus.  I forgot to mention, no other fish, cant see himself, just hubby and I and we are at work all day-not much activity....BUT cat can get up and see so maybe the cause of the stress."  --- from your other follow up.

I'm unsure what tank you have your fish in, but my bettas have a 12h light regulation.  Yes, when the lights first go on it freaks them out, but as I follow light with food, they don't panic for too long!  It also helps them separate day from night.

I've never heard of sulfur burn, perhaps they meant ammonia?  That would be caused by overfeeding and infrequent water changes.  Water changes(daily, at least 25%) would help clear this up.

I do agree with the PETCO people(wait...someone check, Hell might have frozen over!) as for the overfeeding.  I personally don't like using pellets, I find it causes bloat.  My fish are fed a variety of foods - including but not limited to flakes, granules, live and fresh foods, frozen foods.  Things I stay away from are pellets(hard to digest), freeze-dried foods(can cause a very serious condition called dropsy), and any live/fresh foods I've not cultured myself.

While 5 pellets twice daily is too much, 2-3 a few days a week is too little.  I feed my fish once a day, a small pinch, and scoop any food he's not eaten.  You'll get to know your personal fish and his eating habits, and this makes overfeeding easily prevented, but generally give him 5 minutes with his meal, then take out what he's not eaten.

For treatment - daily water changes, daily feeding of a HIGH protein food(commercial betta flakes is my recommendation).  A round of Melafix to promote fin growth and treat fin rot - that's my best guess as to what it is.  Not to worry about how far the damage has progressed, if he's still eating and trying to swim, then he's still trying to live.  I bought a betta with no fins to rehab, and he's been doing great lately, so once you get a handle on the problem, he'll bounce back quickly.

** Sorry for the late reply, we lost power last night, huge storm **