no mobs... on peaceful mode...

1. on 1.14.2 I used to see monk fishes, dolphins and squids.
2. now on 1.14.3 I see absolutely nothing on peaceful mode, I tried re-logging
3. when I turn on easy/normal/hard mode absolutely nothing happens but drowned appears.
4. I tried re-opening minecraft but now I can't find any mobs...........................
5. please fix this problem I need the dolphin's...