Peduncle disease?

Hi, I have a male betta who has what looks like a whitish/silvery withering/ rotting/atrophying caudal peduncle. The caudal fin is very narrow, looks like the top of the fin has collapsed (maybe the muscles have atrophied). I hope this can be seen on photos attached. There are no other signs of this on any other part of his body. Could this be "peduncle disease"? In any case, does anyone know how treatable this condition is, and best treatment options? Thanks heaps.

Hi and welcome to the forum

The fish has a bacterial or protozoan infection.

Find a broad spectrum fish medication that treats, bacteria, protozoa, fungus and treat it.

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To work out the volume of water in the tank:
measure length x width x height in cm.
divide by 1000.
= volume in litres.
When you measure the height, measure from the top of the substrate to the top of the water level.

There is a calculator/ converter in the "How To Tips" at the top of this page that will let you convert litres to gallons if you need it.

Remove carbon from the filter before treating or it will absorb the medication and stop it working.

Wipe the inside of the glass down with a clean fish sponge. Do a 75% water change and gravel clean the substrate. Make sure any new water is free of chlorine/ chloramine before it is added to the tank.

Clean the filter if it hasn't been done in the last 2 weeks. However, if the filter is less than 6 weeks old, do not clean it.

Increase surface turbulence/ aeration when using medications because they reduce the dissolved oxygen in the water.