[helene schoubye]

It would seem unlike though to me that black mosquito larvaes should be ‘bad’ … I use them a lot in summer times too. I avoid the very big and nasty one, but otherwise dont worry about them.
You might have to consider also that chocolate gouramies are not very easy fish in any case. I have never had much success with them. If first one of them falls ill theres a risk the others will also be vulnerable.
I am sorry for you about loosing them, they are so fine fish, – but I have given up with them 🙁