I wonder if something that is getting fed to the MI could slowly be helping it die. Maybe if someone found others that had MI's and made a list of everything they were being fed then maybe it can be determined if there is something there. Maybe it's a strict diet they need, sort of like a mandarin needs pods. So, maybe it's not something that's missing from it's diet but maybe something that should not be in it's diet. Or, maybe it absolutely needs to have a mate of it will die.
That is what people are looking for, the MI I had was in a tank 2 years or so, when I sold this MI it was pushing 3 years in a tank........ It was being fed a large variety of food, green and sponge, it was also fed 3-4 times per day. I can only give my experience with this fish.
It was tough keeping the algae under control because they need food and lots of it, IMO this may play an important role with this fish, before I received the MI it was being fed 3-4 times per day. Example: a variety of meaty foods soaked in vitamins lets say 1/3 of the MI diet, 1/3 variety of greens, 1/3 sponge or sponge based food.
This fish is a non stop swimmer day and night, this is why I stress diet and feeding, IMO I could see how the MI could starve to death in a tank that was not mature, to small or fed 1-2 times per day.
This is not a timid fish and can be very bossy in a tank, I sold it because it was going to get stung by a lion, you could see it heading there. Fast swimmer day and night, turns on a dime, it only take one time to get stung.
It went to a mature 150g tank, and was doing great, he had it a few months, one night it jumped into his overflow and died. Now I did not have a jumping problem but it is not uncommon for this fish either.
This MI was not kept in pairs, though they can be sexed it does not always work out, IMO it is tough keeping one, two is not necessary.
Here are the foods I feed or fed, if marked MI at the end, I do not currently feed but did:
Cyclopeez
Frozen Mysis
Spectrum pellets
Formula I & II Pellets
Angel Formula - MI
Sponge - MI - many LFS have sponges that are dieing or exposed to air, they would save these for me and just give them to me for free. Do not be afraid to ask....
Chopped meaty mixture: My meaty mixture is soaked in vitamins before feeding.
Raw Shrimp
Crab
Mahi, Mahi
Shark Steaks
Cray Fish
Ocean Perch
Squid
Octo
Smelt
Flounder
Red Snapper
Frozen Silversides
Frozen Sand Eels
Mussels
Scallops
GREENS:
Nori
Red, Green & Brown algae - MI
Fresh frozen Peas Thawed
Fresh frozen broccoli Thawed
Banana chunks
Orange slices, in a Nori clip
This is not a fish I would encourage buying, I bought mine from another reefer not from a LFS. My LFS did get a male in when I was keeping the female, it was fat and healthy, the did not order it but just received it. They offered it to me for free and I say no. They tried feeding a variety of foods, it was eating great, about three weeks in to it, the MI just died one night. It looked healthy was eating great but died.
Kaye