deformed guppys

[elsitc2]

I have a 10 gal tank that is 2 years old with an undergravel filter. The temp stays around 73 so I don't use a heater. My guppys are now 3rd and 4th generation and some babies are developing with no "belly" and can't float, they sink to the bottom, but are otherwise normal. Does anyone know if this is a disease or normal for
inbreeding? Very disturbing but appreciate the info...........leslie

[oscarbartoni]

How many guppies and other fish are in this tank? How often do you do water changes and how much at a time? What is your water conditions, pH, ammonia, nitrate and nitrate? Do you have any live plants in the tank? Is it only the newborn fry that are being affected? These are questions that when answered would help to answer your questions. :rolleyes:

[josh]

only females have "bellies" and your fish are probably just swimming near the bottom. :p