Cardinal Plant And Banana Plant Not Doing Well?

[LicianDragon]

I've got plenty of nutrients. I'm starting to think there might be some allelopathy going on between my plants as only these two species are affected. The banana plant has been clinging to life since I put in in the tank(surprisingly it's still going a year later) and the cardinal plant nearly died right off the bat. I'm adding CO2 but have yet to see any changes.