I have been working on getting a number of guppies - approx 50, of varying ages and colours for the tank in the school biology lab.
I left the teacher to set up the tank, i.e. clean it out, partially fill it (about 8cm), turn the filter on etc. This was done a couple of weeks ago.
Yesterday afternoon I added the guppies and one 10 bristlenose, plus lots of floating plants.
I added all the water from my tank and used the cannister filter which had been running on it.
This filled the tank to about 35cm.
Went to look this morning - all dead!!!! Not one survivor.
Got my test kit out and the ammonia was at the top of the level I could test for. pH also at the top of the low range kit I have.
Discovered - the existing filter had not been cleaned by the teacher since the eel died last year (about 6months ago) and had been sitting in a dirty tank until put in this one. In fact the filter had never ever been cleaned at all despite my instructions.
Lesson -
1. never get someone else to do something for you without explaining word for word what you want and checking its been done.
2. never ever add fish to a tank without testing the water parameters first.
I am fanatic about cleaning my tanks and filters.
No wonder the last 3 eels didn't make it!