I have altums in two tanks. I have 9 smaller ones I picked up last Dec. and then a larger pair I bought in March. I also got a half dozen fresh imports in Sept of last year and losing them all inside a month taught me a lot I should have known before hand.
Altums, as noted above, basically only come in wild. Successful spawning is rare. New imports are very difffcult to keep alive as they need very soft water initially and must be acclimated over to tap water a very very slow pace. The 8 I added in Dec had been ins somebody elses tank for a few months and I still used a 50% mix of my soft tap and distilled water. I yook 6 months to move them over to 100% tap. More importantly, then need to be put into an unseasoned tank. Fishless cycle it and d not put in any other fish to start. Smaller fish should be put into temps about 89 which is then raised to about 84-86 fairly soon. My larger pair, having been in the sellers tanks for some 3 years do just fine in 82.
The reason for such a lengthy acclimation process and using distilled or ro water has to do with the fact that in the wild they love in low pH water which is not conducive to a lot of bacteria. The result is that their immune systems are somewhat suppressed weakening their natural defenses against many things they might encounter in the typical community tank. The use of ro/distilled helps buffer them as does putting them into a new tank. Then gradually change the params towards tap over time as well as eventually adding some other dither fish should work fine.
One last note, altums are group fish. They tend to communicate and work in bunches. Some theorize that some of the communication may actually be chemical in nature and thus suggest using some Purigen in the tank initially. I did not do this. If you want altums, plan to get them in groups and look for them in the fall as new imports. Because they are not an easy fish to acclimate from the wild and do not tank breed, it is rare that you will find already acclimated fish offered. I was very lucky with the larger pair.
(Read some about them here
http://fish.mongabay.com/angelfish.htm )
Excuse my poor photo skills and cheap old camera: