Originally Posted by
Ryan
The concern is usually feeding. Discus are a bit more casual eaters than something like severums or geos. If you can make sure the discus get their share, you should be okay with the orange heads. They are pretty passive and if kept in a group will most likely ignore other species. The severums are a bit of an issue just because they can be pushy at feeding time. I've kept severums and discus together on several occasions but it's never worked out great long term for me. I always end up having to separate them when the severums get large and pushy.
Cories are usually okay as long as it's a species that can handle the temps. I'd say it's definitely a no on the silver dollars which grow large and are usually very boisterous and active. Fish like that could make discus nervous.
Keep the temperature in mind. I alway keep adult discus between 82 - 84 and adult geos between 80 - 82. Also, I wouldn't mix them all together in the tank you have now because that's a lot of fish in a 72. Have you thought about upgrading the current stock to a 180, then growing out six discus in the empty 72?