What you’re describing—crater-like holes in the shallow water with “eggs” inside—sounds much more like a fish spawning site than a bird or amphibian nest.
In artificial lakes (especially in South Asia), the most common explanation is:
Most likely cause: fish nesting / spawning pits
Species like tilapia or carp-like fish often create small circular depressions in the lakebed.
What’s happening:
- Male fish dig a round “crater” in the mud or sand
- They clean and guard it as a breeding territory
- The female lays eggs there (or nearby), and the male protects them
These look like:
- Small “bowls” or “dents” in the lake floor
- Sometimes multiple pits close together
The “eggs” you thought you saw are usually:
- Tiny clusters stuck to the bottom or hidden in sediment
- Not large visible eggs floating freely
A common species involved in village ponds and artificial lakes is:
- Nile tilapia
Another possible cause (less common)
Some carp species also make shallow spawning depressions in warm, still water:
- They disturb the bottom sediment
- Eggs are laid in vegetation or gravel, not usually visible as “open eggs in holes”
What it is NOT likely to be
- ❌ Frog/toad eggs (they float in jelly-like clusters, not craters)
- ❌ Bird eggs (no birds nest in water like that)
- ❌ Insect eggs (not visible as crater structures)
Quick way to confirm
If you go back and observe:
- Fish staying close to the holes → very likely spawning behavior
- Multiple circular pits in shallow warm areas → classic fish nesting
- Sudden movement of small fish guarding spots → confirmation
