You know, I hadn't thought of the trigger spitting causing the fire. But, the lights were off for three hours before the smoke detectors went off, he should have been asleep. I say should, but don't know they were asleep. They had been fed at around 8 that night, and the SO spent some time by the tank re-stringing a lacrosse stick.
As all fish, they all had very specific sleeping habits. When the lights would go off, the trigger would disappear into whatever crack he hid in at night, the clown would go to one of her big anemones, the lion would find his cave or sleep vertically against the glass, the frog fish would hang out in his sand burrow, and the tang would still mindlessly dart in and out of the rock work like nothing had changed. The trigger was not active at night at all, so if he HAD done the damage it was well in advance.
I don't know how much his spitting had to play in the fire- he had a pretty good aim and would usually just spit straight into the overflow, thats not to say perhaps he found a way to spit at the lights, or anything else in the hood that could have caused the fire just because it seemed like a good idea at the time.