Hi,
are you sure that they are real C.ocellaris? If they are, you should be happy.

But only one specimen is not a really good solution. I keep three of them since 2 years, from 5" till now 15"-16" and they we`re never aggressive against each other, they really like the association with the others. I keep mine together with big Loricariids like Pseudacanthicus sp. L25 and Hypostomus margaritifer and it works very well. Other cichlids are not so good, cause there are two options: If they are too small (Geophagus) they will be prey for the Peacocks and if they are too big (Astronotus, Hoplarchus) the Cichlas may be domineered by them. I feed them with little feeders and sliced, frozen Tilapia-filet. Unfortunately they ignore every other food I`ve tryed. My other Cichlas like C.temensis or orinocensis had been fed with shrimps, artemia and other frozen food since they were babys, so they swallow that also today with a length of about 10"-15".
I think that you`re Datnoides will not be harmed by them, cause they`re real pussies!
Hope this will help you a bit.
Greets
Patrick