Re: discus blue colbolt (piwowarski)
#2
Your water is OK for domestic Discus strains like these, but there are some other factors to consider.
First are these a bonded pair or are they juveniles? Normally if juvenile you need to start with a group of 6 or so. This is so that you hopefully end up with a pair, and because young Discus are very nervous fish and need to be in shoals to do well.
Next is your other stock. Angels can be kept with Discus, but many recommend they are not kept together. Angels can carry some diseases and parasites that cause no symptoms in themselves, but are potentially very risky for Discus. Angels are also very greedy feeders so Discus may be outcompteted for food and fail to thrive.
Danios are rather too lively for Discus, and as Discus require high temperatures, your Danios will suffer. They really should be kept below 24C where Discus do best at 28C or higher.
Plecs (other than some of the smaller Hypancistrus and similar) are not recommended in Discus tanks as they can easily acquire a taste for the Discus' slime-coat, causing severe damage, stress and eventual death.