How old is your baby?
If he/she is at least 12 months and above, lightly coat the fish with salt and wash it away. Then you can pan fried it till oil of the cod fish seap out itself and then after that use clean fingers to nub it till it become smaller pieces. Then add some rice into it. and then alittle of japanese low fat mayo to cover the smell. Plus alittle seaweed.
If it's steaming, you can try adding alittle of superior soya sauce dilute with water plus alittle bit of sesame oil (Not too much, as it's known to be heaty) and then some baby tomatoes slice half and put into steamer.