I own a 10gallon tank which started off with Four Platies Four Sword Tails and Four small Oscars. In the past few days alone three of the platies have died, as I'm writing this one of the oscars is motionless gasping on the aquarium floor. There are aquatic plants in this tank and I need help figuring out how to deal with this issue. I'm sure its parasites because a day before one of the platies died he had a stringy white fungus growing on his upper fin. Please someone help me! 
