i have had my 55 for about 5 years and started breeding guppies, just recentally i bought some other live bearers and somehow brought a desiese to my tank. i started finding dead fish about 3 weeks ago so i treated them with general cure made by API. finished the treatment and still finding dead fish. so i waited about a week and also tried erythromyacin. but the fish dont look like they are getting any better. some of thier gills are red but the main thing i see is on thier back they are loosing thier colors compleatly and its almost a see through and red could someone help me out?