Hollow Belly or Wasting

Hollow belly are guppies that appear to be wasting away. This is usually due to either internal worms or internal bacterial diseases. Both these diseases are due to poor feeding and poor water conditions in the tank. Correct these conditions. I have found feeding guppies exclusively on a mixture of medicated fish food for worms and bacteria for several weeks can hasten the cure.

Improperly storing fish food has been found to promote fungal diseases, especially in female guppies. The fungus attacks the female's internal sex organs.