Hi tj,
If you have your livestocks in a stable tank for quite a while then I believed they will be quite resilent. A quick change of water & anything to reduce stress will let your livestocks in better stead.
I got quite a similar experience last Friday morning when I just stepped out for work.
My external filter connection to the chiller suddenly gave way & water from the tank started gushing within the cabinet and into my living floor. It was at least 30 min before my family members realised my living floor was flooding with the tank water. By then the tank water left on 1/4 and those soft corals above were drying up. I was contacted only 2 hrs later and asked my family member to put whatever removeable livestock into a pail.
I came back around 3pm and try to put things in perspective. I found the water had slipped into the main power socket (causing breaker to tripped) and the chiller as well. It was almost 5pm when i changed the power sockets, bought seawater & refilled my tank. However my chiller was not working caused it had a lot of moisture from the water. It was only 2 days later that the chiller started to work again.
Luckily most of the my livestocks managed to survive the ordeal and slowly recuperating. I guessed one of the most important aspect is the 'hardware'; make sure there is little or no chance in our setup to cause those preventable failures such as leakings, electrical problems, etc. With those in control, we will be able to concentrate on the 'software' parts which typically are more challenging.
All the best.