What are your parameters is a question I ask far too often. Most issues in fish keeping can be traced back to issues with our water, so when trying to help I will ask that question.

But what do I mean, what are I refering to when I ask that question? What is ammonia and why is it an issue, why do we want to know. Where does ammonia and nitrite come from, and what harm do they cause?

This is for those just starting out, and for more experienced aquarists, hopefully there will be something interesting for everyone.

Ruth McDonald has been keeping fish for over two decades now, and has been researching fish since her master thesis into what fish eat dead bodies took a turn into what fish like to eat. She's taught at university level, and has been running Tropical Fish Keeping UK for 10 years.