Lisa, I had my heterura for 5 months. I would not consider that longterm, but it fared very well. I lost it because of a poor decision(more on that later).
It was a small specimen, at about 2 inches. I kept it in a 40 gallon breeder with a large sand area. It preferred the open sand bed instead of rocks. It would also do an amazing circular dance on the sand when threatened, displaying the blue flashes. I think the most critical thing that helped my fish was lower temps. I kept the temp in the tank between 72-74, and provided lots of oxygenation.
When I purchased it, it was willingly eating frozen mysid. I was able to wean him onto large dry pellets as well.
Sadly I lost him, when I treated the tank with Salifert's Flatworm exit. It's a decision I continue to regret. The dwarf fuzzy looked bad as well, but pulled through. The bluefin did not, which surely proves it is a much more delicate fish. To this day, I feel a horrible feeling in my gut when I remember the decision to treat the tank for flatworms.
I have no doubt my particular fish would still be around. I would have liked to have proven long-term success with this fish, since so few have kept it past a few months. I think I was lucky to find a healthy specimen locally that was already accepting frozen food. After a month in my tank, it begged for pellets like a puppy dog.
If I were to give advice about this fish, it would be the following. Fundamentally, I think this fish doesn't deal with stress well. I get the impression stress is a toxin for this fish, much like it is for sharks. This makes them VERY poor shippers. I also think this fish needs more oxygenation and lower temps. And lastly, I think they need a low stress environment.
At the time I kept it, I had contemplated moving it to my 180 reef before adding flatworm exit to the 40g. I hesitated, because I feared my helfrich's firefish would become food. Now, I no longer keep the helfrich's, and have not added any small fish to my tank. The reason for this, is that I hope to find another bluefin one day. If you hear of more shipments, please PM me.
Someone wrote a great wiki on this genus:
http://en.wikipedia.org/wiki/Parapterois
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