I have used deiffenbachia for the last 3 years as a help in reducing nitrate in my 180 gal, and at the same time kept a Panamanian Pleco, that has gone from 4" to 8". I provide plenty of waterlogged wood for the Pleco to chew on, beside the algae, and occasional fish or shrimp chunks as added protein.
View attachment 1495493
View attachment 1495495
Beside the daiffenbachia, the tank is heavily planted, with aquatics like Vallisneria the Pleco doesn't bother, and with other (often considered)"Toxic" plant species, like Arium. Seems, Plecos have an instinctual aversion to eat, what they shouldn't.
View attachment 1495496
Below, eating a chunk of ocean fish flesh.
View attachment 1495497
But this is not an isolated case, I have kept many Pleco's over 50 years of fish keeping, using a number of what are considered "Toxic" house plant species.
View attachment 1495494