I would build from scratch and do it properly with a 200-300L tank + sump, skimmer and LED lighting etc. Make it a learning process, $3k is a good budget to do it with.
I was the first year of ncea... crap system.
Also I don't think you young people understand that school cert you had 5 or 6 subjects and there was only a single exam at the end of the year for each class. No achievement standards and not splitting into multiple papers.
It doesn't really matter except if you want to do a degree where they select the best candidates like med school or engineering.
For those going on to uni, do what will make you happy, not what will make you money.
Congrats on your results though.
Wow I would be furious. I hope you are going to take them to the disputes tribunal for the cost of replacing the fish. I would say mcrudd is right in that they dumped all the food in on one day.