Hi John
I'm not absolutely sure which
Naso you have.
N. unicornis and
N. lituratus seem to be fairly common in the trade, so I'll presume it's one of those two.
Both are known in the wild to pick at benthic brown macroalgae, and the Genera
Dictyota,
Hormophysa and even
Sargassum get mentioned a lot. Maybe they have a tooth for mannitol instead of starch (as in
green algae), who knows?
Spirulina seems awfully common in the trade, but it isn't the most nutritious (or even flavorful) of the greens. It has its uses, but try to get a small piece of LR with either
Dictyota or maybe
Padina growing on it, and see if the fish learns to pick on it. The other
brown algae mentioned earlier are too leaky in a reeftank, and may yellow your tankwater.
All this talk of picking at veggies aside, these are unicorn tangs we're talking about, and there's a strong pelagic (or open-water( streak running in them. For this reason, planktonic food will likely always be on their wish list. Furthermore, my recollection is that none of the
Naso tangs are pure herbivores ---and indeed some are mostly zooplanktivores, so don't begrudge your pet's tooth for animal protein.
Maybe you can try to verify your fish species, then try your luck at fishbase.org, and see if their servers and mirrors are able to handle one more request, and check on the known diet of your fish.
In any case, unicorn tangs can be very adaptible when obtained young, and given either a transition food or the threat of starvation (hehehe), they can learn to eat all manner of commercial preps ---maybe even those green flakes of yours.
hth
