Black dot on my Beta fishes fin

Question
Hi, thank you for your time.  I have owned my Beta fish, his name is Fred, for about a year a half now.  He is much more active than usual and over the weekend, I have noticed immediatly that he has a black dot on his fin and it is on both sides right in the middle, but not attached to his body.  What is it and how do I get rid of it.  I love this little guy, he has so much personality, I would be really sad if he was sick or died.  OMG! Thank you again, Jen

Answer
Hi Jen,

Your Betta is an old man. Bettas usually only make it to around 2-3 years old and he would have been a year old when you bought him.

This sounds like Black Spot disease. This disease usually affects coldwater fish such as Carp etc, however it is fond of a few tropical species.

The spots contain the larval stage of a trematode intestinal fluke. Sounds like death, however it's relatively simple to deal with. Mild infections of black spot rarely damage the fish and because of the complex life cycle of the Larvae it is not contagious to other fish.

Modern anti-parasite treatments should kill the parasite. However, once the spot has formed it can, sometimes, be there for life. To avoid the parasiite re-entering the tank; keep a close eye on snails. They're the buggers that carry the disease from one place to the next.

Good Luck

Tom