So my partner bought the fluval roma 125 from pets at home in december after cycling he added...over a few months 2corys 5 indian guarmis dozen neons 3 balas and a pleco o and some guppys he had the internal filter thst came with it and a fluval 206 external everything part from nitrates were 0 ph 7 then april his fish were dying handfulls at a time water parametres still fine then I noticed some were looking white and stringy so I used some waterlife is it mylazane or something haven't gt the bottle to tell u now followed 5 days of treatment still fish were dying eyes dissappearing getting covered in stringy white stuff not producing mucus sharks literally swimming round with no heads after the meds ammonia snook up due to the medication killing the good and bacteria off we were told I did pc reg to keep that down by the end of april only 1 mega strong guarmi was left..I took the bold and stupid choice to move him to my molly n platty tank n he's thankfully thriving now so I made my psrtner empty his tank wash gravel glass decor and start again added new plants but didn't put devor in yet so I helpd him there reattached filters got it running we went away in june when we got back cycle was finished ammonia was gone was ready to go so out of my 180 which params are fine I gave him 2 paradice and 3 guarmis and 3 congo tetra all of which are over a year old he added thm by floating and slowly adding his water then netting them out 2 hours later only my 2 paradise are alive but param n temp are still fine help