Small fish

Small fish

Observation - Small fish . Description: Small fish found in pond in wildlife area. Approx 6cm in length. I thought initially that it was a stickleback but it doesn't appear to have any spines. Any help with ID would be appreciated :-)

Small fish found in pond in wildlife area. Approx 6cm in length. I thought initially that it was a stickleback but it doesn't appear to have any spines.
Any help with ID would be appreciated :-)