2 dead frogs within 2 days

[spitz666]

ive had these frogs for about6-7yrs. i quarentened the other 2.they arent happy about it.not sure why they died. other 2 sem good,they are eating.i have tad pols int he tank and im not sure if i should start over and disinfect the whole thing,and if so what to do w/ tads in the pools, i let them develop natually in the tank.any ideas? thx bruce.