The establishment of an intestinal microflora in developing goldfish (Carassius auratus) of culture ponds.

The bacterial flora in the intestinal tract of goldfish (Carassius auratus) was investigated at different stages of fish development. The floras of the diets and the water and sediment of a culture pond were also analyzed. The total counts in the intestine ranged from 2.2 × 10(6)-2.1 × 10(8) cells g(-1) wet weight.Aeromonas hydrophila, A. punctata, Pseudomonas, Bacteroidaceae andClostridium species were the common components in the intestinal tract of goldfish from larvae to adult stage.Bacteroides type A appeared at 44 days with a density of 10(3) cells g(-1) and then predominated with densities of 10(5)-10(7) cells g(-1). The intestinal microflora of goldfish become relatively stable after 67 days of hatching. These observations suggest that the intestinal microflora of adult goldfish becomes established approximately 2 months after hatching.