I was told my neon tetra had possibly white spot. I moved them to a different tank. I put blue planet white spot treatment in the tank they were in. I put 5ml in 40l tank as instructed. The next day 2 guppies died. I continued the treatment after the 3rd day as instructed & had 2 other fish that died & no sign of white spot on them. Could they have had white spot before it being visable? Could it be the treatment? Should i stop? How do i test fungus in the water? Ive had the water tested for ammonia & ph at the pet store & was fine.