yeah your bacteria colony just wasn't large enough to support the number of fish you had you still need to get rid of the ghost knife fish asap
while water changes and dechlor can contribute to ammonia in a small way your issues is not the water changes (the changes also slow the cycle) the trouble is you have fish trying to live in poison water that being said the water changes aren't really optional
while water changes and dechlor can contribute to ammonia in a small way your issues is not the water changes (the changes also slow the cycle) the trouble is you have fish trying to live in poison water that being said the water changes aren't really optional