DISEASE: TAIL ROT AND FIN ROT
In the picture above, betta has has a rotten tail and fins. This disease comes mainly from dirty water. Accumulation of rotten food and fish waste kept un cleaned for a long time causes this problem. If water is kept clean and fish/food wastes are cleaned time to time, your infected beta will recover soon.
Betta’s fins and/or tail seem to be getting shorter and shorter. Or they seem to be falling apart and dissolving. He may be still active and eating normally, or may have stopped eating, fins may be clumped, color may be pale and your betta fish may be sluggish.
Do a full jar water change. Use tetracycline or Ampicillin combined with Fungus Eliminator . Change water every third day and add a new dose of same medication. Continue until fins/tail stop receding and start showing some new growth. This may take up to 4 weeks, so don’t give up. Once rot stops and fins start growing back you can stop treatment, but not before then.
Note: If the rot is very slight or mild, you could use Maracyn I and Maracyn II. These medicine can help but are not very powerful. They come in hard tablet . You’ll have to crush them into a powder before you can administer to a betta. A tablet treats 8 gal of water, calculate accordingly and please do not over medicate. Over medication is dangers and may have adverse effects on your Bettas.