Chris Bentley

You could try Invie breed-M. I have used that and mixed with gelatin to improve water stability. It is intended to be used as a fully balanced semi-moist diet. So it is not going to be like a vitamin/mineral pre-mix, but could probably be inserted into raw fish and give them a boost that is formulated for broodstock. If you can get the fish onto the semi-moist diet, that product is well formulated ...

We used to break up children's chew-able vitamins and put the pieces inside the raw fish. Low tech approach but effective. You can even get them with extra DHA now.