I know the ottos are pretty lazy at times but the one was ill, he's got clear signs of the ammonia poisoning and before i did about 6 water changes yesterday he was just sat under the filter getting swotted by guppy tails and not moving. But happily he's gotten better, more lively and it looks as if his gills are a bit less red.
Like i said i know there's still a lot of hard work ahead of me but it's worth it if i can get my fish healthy and happy again