I'm experiencing the same problem right now. Actually, it has progressed
beyond the stiff, white fin that you mention and started to disintegrate to
stumps ... exposed fin rays are now noticeable.

Not sure what would have cause the problem? I tested the water quality and
it seems OK, but at the same time I'm a begginner.

0 Amonia, 0.25 nitrite (new tank), 11 degrees of hardness, 8.2 PH ... would
the high PH level cause this problem in a beta? Anything else I should test
for? Maybe nitrate as well ...

In any event, I've moved my beta to a 1 gallon tank, which is always sitting
around, waiting for such cases, with pre-treated water that had plenty of
time to build a sufficient bio-filter. I'm going to be administering daily
25% water changes, and will be purchasing some salt, and maybe anitbiotics,
which have been recommended on a number of sites I visited.

I think the darker tank is a good idea. I noticed my Sashimi was hiding
under rocks, and light may have been part of the problem. Right now, he is
at least floating around in the "hospital" tank, which is darker, whereas
before he was constantly hiding, and moving very little.

Also, the water PH in the hospital tank is 7.4 ... and it has always been as
such ... the PH has gone up in the other tank when I introduced a plant into
it. Do plants raise PH levels?

I'll keep you posted of how the recovery goes. In the meanwhile, if anyone
you seasoned veterans could shed some light into the problem, your advice
would be greatly appreciated!

BTW, the fin loss is not permanent ... it will grow back most of the lost
tissue within a few weeks, if the fish is on the way to recovery, of course.

"PurityFailed" wrote in message
...

OK. Now I'm panicking. My boyfriend's betta suddenly showed a nasty
white
patch which started directly behind his dorsal fin yesterday. His
beautiful
tail is now stiff and slightly whitish. He's about a three inch fish and
the
patch is about a half inch from the base of his dorsal extending towards
the
tail.

Luckily we found an old 10g tank last week in the garage which we'd washed
out
and checked for leaks anticipating at least a fishy cold or something. So
yesterday we bought a Hagen Biofoam sponge filter, air pump and tubing
(the
good green kind), Mardel Maracyn tablets and a heater and hang-on
thermometer.
I decided to just buy a glass canopy and opt out for a light right now.
I'm
thinking that a darker tank wouldn't be a bad thing for Vlad right now.
Am I
wrong?

Temp in the tank's 70F where the tank he came from was 75F. I've read
that
temps lower than average make absorbing oxygen a little easier for sick
fish.
I know I probably should have stuck to bare tank, but I put in a plastic
plant
and 2 lbs of river stones in there for a bit of comfort. The stones will
be
boiled after Vlad is moved from the tank and the plant will be tossed out.
(Hopefully after a recovery. :/ ) He seems to appreciate the scenery as
he's
been hiding in the leaves or resting near the rocks most of the time.
Every
now and then he'll make a circuit around the tank mid-level and dip up for
a
gulp of air.

He seems to only be moving with his pectorals and not his usual squidlike
movement. This has led me to believe that perhaps he's lost the use of
his
tail. Maybe permanently? Respiration is actually relatively normal.
Since he
was up at the top of the tank when I came in today I put a flake in there
which
he tried to go after but gave up when the filter output blew it away from
him.
I removed the flake... Oh man...

I'm also suspecting that one of my Platys might be getting it. A shade
lighter
tint along his back. Should I put him in with Vlad? Any suggestions on
an
emergency extra quarantine tank?

Water change yesterday and another due today. My plan so far is to dose
Vlad's
tank for the reccomended 5 days and consider his condition again after the
5th
day. If it's gotten worse then I guess I'll have to try to find a vet
around
Columbus, OH that carries fish anesthesia. That's really the only way I
feel
comfortable about it.

Thanks for reading through and pre-thanks for ANY replies.

Jessica
(Oh please let the tank cycle...)