My Tank and Various FIsh

Question
Hi Lynda,

Im new at owning fish and have been experiencing some issues with my new fish.
I have Clown Loach, Angel Fish, Tiger Barbs,Pleco, a catfish (not sure on type) and Silve Dollars.
My fish have been acting really strange lately, the silver dollars seem "tired" and dont do much any more and the same goes for my clown loach. My fish were very active when i fist got them, they dont seem to be eating as much as they did before, and yesterday one of my angel fish died... would you know what could possibly be wrong with the fish or my tank? I have done a water change and added some stress liquid as we were advised this could be the case, but there doesnt seem to be a change. Please help!

Answer
Hi Claire,
When fish are sluggish, and dying, it is usually your water quality that isn't good.  Check your ammonia, it should be at zero, and if it isn't, do water changes everyday until it is.  Ammonia is the number one killer of fish.  Check your nitrates, very important that you do.  Check your PH, for these fish it should be around 7.0...also check your water temperature....it should be 78 -80 degrees.  I would also like to mention that tiger barbs and angel fish do not make good aquarium buddies.  Tiger Barbs should be kept with other fast schooling fish, as they like to nip on slower fish...they should not be kept with chiclids.
Hope this helps.
Lynda