David, I had the same concerns. But I tried it, and the food has only a slight difference in color. It's sinking ability is the same as without Naturose. The oil is 2% by weight, and is not significant. There is no film on the water, and no more mess than the food provides normally. It appears dry in the feeders, and leaves no residue. I think the food absorbs the oil and the fish eat it. Fish oil has a fabulous fatty acid profile, being fish oil, so perhaps it adds nutrition as well.
On the other hand your fish are perfectly beautiful. I see no reason to change what you are doing so successfully, unless you want to.
Normally I have very few misbars, but I had an unexpectedly large nest hatch this time in the picture above, and I was unprepared. I did not have enough rotifers, and this is what I account for the misbars in this group.
In fact it cannot be blamed on the naturose, as I don't give them naturose until they are eating Oto B2. By then, the bars are already formed. Oto A and B1 are fed as it comes from the store. I only topdress the larger sized B2 and C1.
