Thank you!
This may seem pretty esoteric but at teh top of the list I think is a holistic view of ecosystems and the importance of microbes. (PaulB mentions this once or twice.
![Smile :) :)](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png)
)This was concept was solidified in a very brief conversation 23 years ago talking with the director of a local hospital's infectious disease department when she pointed out good bacteria in the wrong place is bad. My take away (and other authors certainly had a part in this realization) was balance in an ecosystem was important and outweighed the needs of any single species in that ecosystem. Pragmaticly what this meant was before doing something to save an individual animal, fish or coral or invert, weigh it against what's best for the ecosystem.
Second I've gotta say redundancy. I try to set up my systems to minimize any risk of a dieoff WHEN any one piece of equipment fails. One of the simplest ways I've found of doing this is adding air pumps and I am particularly fond of Penn Plax's B10 which turns on when power fails and will run several days. Unfortunatel the biggest preventable problem I've seen over the years is well intentioned people trying to do my cleints favors by turning off heat or air conditioning. The yellow tang in the thread I linked to in my first post was killed this way. Visiting family members turned off the AC when they left for a day trip heating the tank up and killing many of the fish and a significant number of corals.
Third, and I've seen this posted by other experienced aquarists here, is keeping it simple. Ease of access and ease of replacing equipment is critical in my experience in long term success. Some of the saddest things I've seen is when I'm called by someone to help figure out what's wrong and I find a heater or motor buried under a fancy plumbing system where it couldn't be seen or checked that has failed and exposed metals to saltwater. A less obvious problem with some of these equipment heavy systems is a lot more heat is generated and may cause the system to run several degrees above ambient. Throw in the fact corals can have an internal temperature 1 oe 2 degrees above the water surrounding them and it explains why an aquarist suddenly has a few corals die when everything seems to be fine.
I see I'm starting to rant so 'll get off my soapbox now.
I still haven't had most clownfish make it to 20 years. 10 to 15 seems to be a good average. This bothers me some as the record for a wild clownfish is 28 years for a Tomato clown. But longevity in clownfish may be something like domestic cats where the record is 34 years but ask any vet and 20 years is a pretty old cat. So record aga and expected age may be very different numbers.
The only damsels I keep are Chryseptera sp. I avoid all the larger species and any that don't keep their juvinile colors as adults. For the Chryseptera species I've kept 10 years is pretty good. I will not keep any Chromis,there's just a very poor 1 year survival rate.
I've had several dwarf angels live 12 -14 years which I'm pleased with. In the wild life expectancies are 1-11 years. The tanks I've kept long term have all been on the smaller side of 500 gallons so I've not kept many large angles. The biggest problem I've had is they outgrow their tanks and finding good homes for them in bigger tanks is not easy.
The problem with wrasses is what we usually get are supermales which in the wild often only live months. These are the ones that can really start to look old after just a few years. The best way I've found to describe it is they start to look "ratty" like a cat will when it gets really old.
Cardinal, basslets, gobies and blennies. Some people may think this sad but I haven't really payed a lot of attention to these fiah for the most part. I know I've had Lawnmower blennies around 10 years. I've had Pajama and Bangii Cardinals 5-8 years. 3-4 years seems to be a good average for Anthias but I thinkk the longest is 7 years (I suspect large groups of females where a male is allowed to change naturally in a really big tank may have better survivalrates personally). I've avoided psudochromis mostly because I can keep several grammas together and have some interesting behaviour displayed as well as keep different species together.