Well, if your aquarium is only 3 days or around a week old, then the ammonia is due to the aquarium still being in its cycling stage (this will take around 4-8 weeks to complete depending on your filtration system). Add something like cycle / stability, to help with the cycle, and do 25%-50% water changes w/o touching your filtration media 1-2 time a week.As you already have too many fish for a new system, thats the best regiment for keeping the cycle going and preventing fish death. You can also run things like chemi-pure filters and/or polyfilters to help with those waste levels.
as for different species. I would recommend chinese algae eaters, golden algae eaters, dwarf plecos such as bristle nose plecos, and horse face loaches. There are also otocinclus, which are great, but they max out at 1" and wouldnt mix too well with semi-aggressive fish like gouramis and tiger barbs. |