>own 2 platy breeds
>the first, the one i have the most of, is fine
>no deaths in the past year
>babies are healthy, 1 retard born ever

>the second population had one die within 2 weeks (died in labour of her second clutch)
>another died recently (vanished, eaten by snails)
>multiple babies born deformed, unviable, or become tumour ridden

im guessing no. 2 are doing so poor because they are low quality genetic stock, but it still makes me feel guilty. especially the since i wasnt able to recover the fish and autopsy the second death. am i wrong and dumb or should i cut their lineage off at generation 2?