Black Ghost Knife
Congo Tetras
Roseline Sharks
Filament Barbs
Striped and Spotted Raphael catfish
Clown Loaches
Blue Botia Loaches
Will any of these fish stress the discus out?
I have personally experienced clown loaches chasing discus because are attracted to the mucus that discus exude. Others have had this work out fine. I would never take the chance again.
I would first determine if the discus needs are met and then look at the compatibility of each other fish based on these needs:
*temperature: 82-84 degrees
* feeding- discus eat slowly and cannot be with fish that out-compete them for food.
*compatibility: discus are gregarious and need to be in group of at the very least- 5.
* activity: discus are very low activity and are diurnal. The move very slowly ( in terms of the fish we keep in aquarium) so need to be with fish that are not too active or move to quickly. They are active in the day and do not do well with nocturnal fish.
With this, I would scratch all the fish you have listed with the exception of Congo tetras- this may work, but you will need to make sure feed enough that discus will get enough food.
In the 16 years I have kept discus- these are the fish I have successfully kept with them:
Corydoras: c. adolphi, duplicareous, and weitzmani.
Characins: Hemigrammus bleheri ( Rummy nose tetra), Paracheirodon axelrodi (Cardinal tetra), Paracheirodon simulans (Green neon tetras- adults), Hyphessobrycon pulchripinnis ( Lemon tetra).
Cichlids: Mikrogeophagus ramirezi ( German and Electric Blue varieties).