i agree with madding. i had a chinese algae eater in with a senegal bichir and for the longest time it wasnt a problem until that "one day". spots where the slime coat was missing started appearing on the sene. and thats when i separated them. ive heard of certain combinations of sucker fish and bichirs living in harmony and thought i was one of those cases. dont have any experience with plecos and bichirs, though i personally wouldnt risk it.