Thanks everyone for the encouragement. Having larvae is one thing, getting the larvae to metamorphose into a fish is another. For red heads I believe it will take around a month, about a week longer than dottybacks.
Previous try I got them past 2 weeks but I gave up as they did'nt seem to grow and I only had 2 larvae left. Now I still have easily 100+ larvae estimated and they do seem to be growing. I might have underfed them the previous attempt. I would have used a bigger container for them for less work & less monitoring, but have space constraints at the moment so got to make do with what I have.
Apologies for the poor quality pic but it is hard to take photos of larvae that small without a microscope to magnify them.