I trick train my fish to eat what I want them to .
I feed frozen blood worms regularly and definitely disagree on whether they are good for fish or not , but what do I know and who says my fish are healthy and happy ?
This is how I trick train them .I add a food I know my fish will eat and add little amounts of what I want them to eat with it. Over time I add less of what they want and more of what I want. They eventually start to eat what I have added. I train all my fish to eat pellets [like NLS ] and flakes but do spoil my breeders and fry with frozen or live..
This could easily take 2 weeks with healthy fish before you can skip the fishes preferred food ,but has worked on almost all fish I have kept...