Dwarf Lion Fish

Question
I need some help trying to understand a few things, I've been dealing with saltwater for about 9 years now, and I've really grown to enjoy it.  I've set up a 55Gal Indo-Pacific region tank, housing only a few fish. I did notice a small water quality issue about 4 weeks ago when my Porcupine Puffer was showing signs of HIGH PH, I did 2 water changes (just to be save) over a 3 day period and the PH is was stable at 8.2 and within 2 days my Puffer was back to normal, happy eating, playing (loves to rub up against my hand while he's in the tank) now today I noticed that my Dwarf Lionfish was acting funny - I check the water but all the test were perfect, I looked for ick and eye problems but nothing, and I am not sure why he died a few hours later.  Not sure but do you think that the PH issue could have caused my Lion to get ill? I had once heard that they have a problem digesting goldfish, is that true? How long do Dwarf Lionfish live? I feel like I lost one of my kids.  Any help will be greatly appreciated.

Answer
Hi Eva. I am sorry to hear about the loss of your lionfish. These fish can live for 8-10 years in the aquarium and are rarely affected by less then perfect water quality. If you were feeding your lionfish a diet that consisted mainly of live freshwater feeder fish then this is the reason why he didn't live as long as he should have. While freshwater fish are really the only available live feeders, they are not of the proper nutrition to sustain any saltwater fish long term. Freshwater feeders lack HUFA's(highly unsaturated fatty acids). This is a vital nutrient for saltwater fish and when deficient in this, a saltwater fish will eventually fail to thrive. Freshwater feeder fish should only be fed to a lionfish during the vital first few weeks of introduction to your tank. They should then slowly be weaned onto frozen marine fish foods such as krill, silversides, clam or prawn. This is a very common mistake that is made when keeping these fish. Live freshwater feeder fish can also harbor many diseases and infections that can lead to infections in your lionfish. I don't even recommend feeding feeder fish to larger freshwater predatory fish because of this. All lionfish can be weaned onto frozen with some effort and a lot of patience. Once again I am sorry to hear of your loss. I have a dwarf lionfish and he is one of my favorite fish as well!