I’ve long learned not to put my hand in the tank after the lights go out, but every now and then I deal with things in the “twilight” (blue lights on, as in “daylight”, but white lights off) and get totally rebuked for it.
Here’s my effort to right coral that was tumbled by too many hermit crabs:
A few seconds, 7 stings from some tank-dwelling creature (my bets are on the web-spinning snails), and it’s all benadryl and ice. Nice. Thanks, fishtank.