The only way to be sure to kill all the cyano
bacteria in a tank is to do a 5 day treatment of Erythromycin. First you want to vacuum or remove as much of the cyano
as possible then start your 5 day treatment. On day 6 do a 50% WC
. Erythromycin won't harm BB but if you have a lot of dying cyano
you can have an ammonia spike which is why you want to do a large WC
after treatment. Many people use Maracyn but any Erythromycin sold for fish is perfectly fine to do.
Rarely will any fish eat cyano
. It actually releases toxins and is nasty stuff.
Be sure your nitrate levels are at least 10ppm as cyano
low levels makes a tank easier for cyano
to get established in.