Angel fish urgent advice needed!!!

[Ollie_butts]

Hey guys I'm new to this, I've had my tank 5 months been doing 100% water changes every month and 30% weekly, I've got two filters running and feeding twice a day. 3 days ago I did 100% water change and then all the fish started dieing!! I sorted my ammonia levels and chlorine out and that seem to solve the problem but I've only got 4 fish left from 15 both my angels we're slow and floating around uncontrollably but now ones recovered and is acting like normal but the other is still floating around and hiding behind the filter it won't eat and when I move it back into the tank it swims then hides behind the filter again what should I do? It's normally the most aggressive active one! Also whilst they were all dying they were at the top of the tank heads out the water, why could that be as the temp and oxygen were fine, hope someone can help thanks

 

[Darylb]

never do a 100% water change you are taking out all the beneficial bacteria you should just keep up the 30% water changes weekly

 

[Ollie_butts]

Yeah I know that now but I'm a bit OCD and like It to be crystal clear all the time, i do wash the filters in the old water so they should still have to cycle in them when I fill it back up? I'm not going to do 100% changes now anyway lol any idea on the angel (how to stop him from dying)

 

[Darylb]

i dont really know what you can do just hang in there and hope for the best if you want clear water maybe invest in a UV steriliser it should give you nice clean looking water