Hi all i currently have a 20 gallon medium planted tank with about 20 guppies (3 female adults and the rest are babies from 1day old to 6 mths old). Tank had been running for about 1yr plus and the 3 adult females are raised from babies so i had them about 1yr plus already. previously bought 3 males from a fish shop. 2 of the males had Camallanusworm which i had treated and they are doing well for about 3 months and then 1 of them started to waste away, didn react to medication subsequently died. then about 2 to 3 weeks later the other one died suddenly and the last male also died suddenly just 3 weeks ago. like in the morning when i was feeding it was still very active and i saw it eating a few pellets tat i had put in then i went to work and it was dead when i came home. So now 2 of the 5mths old guppies are sick. one started not eat about a week ago. initially i quarantine this in a 3 gallon tank and added some aquarium salt then a few days later it stared having white poop so i started API general cure. tonight will be the 48hrs later that i have to add another dose. so far it is not pooping white poop anymore but it is still not eating. then this morning, i notice the other 5mth old guppy looking very lethargic and its scales at its bottom tummy is raised. He did not show any symptoms at all. i feed them once daily sparingly and i observed to make sure everyone of them is eating so he is still active and greedy yesterday. i was rushing to work this morning so i took him out and put in with the other one already in the general cure soak. Now i do not know if i should continue to add another dose of GC as planned? any1 know what is wrong? My tank parameters are ok. Ammonia 0, nitrite 0 and nitrate 5 usually. water changes done once weekly about 25 to 50% change. last WC on monday i also have 4 cherry shrimps which i had kept for about 4mths already. fishes are fed a mixture of hikari fancy guppy pellets and new life spectrum for tropical fish with garlic, and frozen brine shrimp on different days. Should i started treating the whole 20 gallon just in case with General cure also? What could be happening?