One of the guppies that I bought a while back has died.
Not sure if it was due to the infection but seems that the rest are fine.
Will attribute it to old age / sickness before doing any further treatment of the tank.
My arowana also did its first jump of out the tank today. It flopped about on my table for a while before I could put it back into the tank. Hopefully there's no major damage to it in the long run.
