Yes, it is a common assumption that the fish got sucked into the filter. But, healthy fish can avoid the filter with ease. Fish don't maintain their integrity for very long after they die.
No, it's not always irrational to say "such and such". One need not have a friend die in a drunk driving accident to decide not to ride with drunk drivers. That's just making a smart decision. Drunk driving and dying are closely related. However, the examples I used reflect the nature of the issue, which is that one has no bearing on the other.
125 - BGK, chanchito cichlid, pictus cats, silver dollars, palmas bichir
125 - cichlids (severums, bolivian rams, chocolate), rainbows ( turquoise, red), loaches (angelicus, zebra, kuhli and horseface), plecos (BN, RL and clown), denison barbs, tiretrack eel, pearl gouramis, betta
90 - Congo tetras, african knife, upside down cats, spotted ctenopoma, kribensis, delhezzi bichir
2.5 - betta