Anyone know what's wrong with my betta?

Hi,

I bought a new betta a few weeks ago and noticed some spots on him as
soon as I got him home. (I bought from a lsf I have never used before
and will never use again now - I found out later that they had a bad
whitespot problem and were still selling the fish regardless.) At the
time it looked like very typical white spot and not much else (a few
small white sugar grain type spots on pectoral fin and on flank near
operculum) so I treated it using a malachite green based med by King
British but saw little change after two weeks (which was much longer
than I have ever had to treat before). The only difference was that
some of his old spots fell off and new ones appeared.

After taking some advice I cleared the tank of the old meds - put in
some active carbon (new to replace that which I had removed before
starting to medicate.) 48 hours wait and 3 X 50 % water changes and I
then gave protozin a try (by waterlife) which I think is methylene blue
based (being sure to remove the carbon again before dosing). I thought
it would be good to try because it is a broader ranging anti-parasitic
than the white spot. However this seemed to have even less effect than
the King British Med. The Ich got worse.

After more advice I tried adding aquarium salt and raising the
temperature to 85F. This seemed to have some effect but the betta
seemed very uncomfortable at that temperature and started sitting in
plants at the bottom of the tank with his fins spead out as if he was
trying to cool himself. I kept the tank like this for 3 days but gave
up on it in the end because I was worried about him being too hot.

I'm now trying the Interpet Whitespot treatment. I am on day 5 of this
now and the betta is not looking very much better. The typical Ich
spots are finally getting less (which is good) but now he seems to have
this white stuff under some of his scales which sometimes dangles out
and sometimes disappears (see picture at
http://www.muddylittletaoist.org.uk/...der-scales.jpg and at
http://www.muddylittletaoist.org.uk/betta-probs.jpg). ?anchor worm
?skin flukes? It seems that he might have more than one parasite
problem. I wouldn't be surprised given the things I've heard about the
shop in question since I got him.

Tank conditions a

NH3/NH4+ = 0 ppm
NO2 = 0 ppm
NO3 = 15 ppm (same as tap water)

Tank is 5 gallons (Imp) and is filtered and kept at 80F. I have 8
watts of light, plants and am running air bubbles to keep the O2 up
with the meds in. Normal waterchanges are 50% twice weekly but I've
had to adjust that around the meds (doing changes just before next
dose.)

Other behvaioural signs include flashing and hiding out at the bottom
of the tank (definitely not normal for him).

I really want this little guy to get better but I am all out of ideas.
I've tried everything I know and taken advice of very experienced
fishkeepers near here and still have a problem. All meds have been
given exactly according to manufacturer's instructions. I've never
experienced a fish illness which is so difficult to get on top of.
Have I misdiagnosed this? Does the betta have multiple problems? Or
am I doing something else wrong? I've successfully treated whitespot
before but nothing is getting him clean and well - I just don't know
where to go from here.

Please can you guys give me some advice? Have any of you ever had a
really persistant Ich problem? Or does he have another problem too? I
am quite prepared to tear down the tank - I can put the betta in the QT
tank while I do it (although it's not cycled.) Or maybe I should buy a
UV sterilizer (although I'm secretly hoping to win one in an offer in
PFK magazine). Maybe I can borrow one? At this point I will try
whatever works and is in the best interest of my fish.

Sorry to have rambled - I'm quite upset about all of this.

Thanks,

Muddy