Originally Posted by jono088
Yeah it was quite a lot which was what concerned me.
I use API Stress Coat in the water. No beneficial bacteria, is this something I should be using?
For sure. It helps break down fish waste and reduce toxicity. Also, it will form a beneficial colony in the filter sponge (never, ever clean your filter sponges with soap, or plain tap water as it will kill this good bacteria). So you'll have mechanical filtration (your filter trapping nasty particles), and biological filtration (helpful bacteria breaking down poop, etc). The beneficial bacteria have a life cycle, so they need to be replenished weekly, and after water changes.
Your local aquarium supply will have bottles of this good bacteria. Just follow the dosing according to tank size. And this may have been one of your problems with dying fish as well. Your tank hasn't been cycled it sounds.