Almost any amount of research will reveal numerous recommendations from discus-keepers who all agree that these fish need high temperatures, do best in single-species groups and definitely prefer soft acid water.
So, buying a single discus and plopping it into your mixed community aquarium in much cooler, harder, higher-pH water...based upon the assurances of a single guy who swims against the current by telling you it'll work out great...and who is trying to sell you something...well, you see where I am going with this.
You can search and search and eventually find somebody to tell you exactly what you want to hear. But if you need to wade through multiple people telling you the exact opposite...that's a hint that you need to reconsider your plan.
So, buying a single discus and plopping it into your mixed community aquarium in much cooler, harder, higher-pH water...based upon the assurances of a single guy who swims against the current by telling you it'll work out great...and who is trying to sell you something...well, you see where I am going with this.
You can search and search and eventually find somebody to tell you exactly what you want to hear. But if you need to wade through multiple people telling you the exact opposite...that's a hint that you need to reconsider your plan.
