This has been a long process, the fish are not yet back as three "guinea pigs" have died- firstly the salt level was too high, but now that is ok. The last one died on Thursday, so I am trying all angles.

These are the plants/ferns that I have added:
I don't know all their names, mostly ferns and some reeds:

Waterfall now:



Does anyone of some/any of these might be poisonous to have caused the deaths?











Thanks for any advice