At the start of the year I want  my students to discover what a great subject Biology is and there is no time to waste in an IB course with such a lot of content.  I usually start the year with a microscope practical, also reminding student of lab safety. Cutting onions is 'old hat', I want to get them excited?

This is where the secret life in my laboratory aquarium takes centre stage.  Students prepare slides to see if the conditions in the aquarium are good enough for the fish.  Their task is to find any evidence of parasites that may harm the fish.  After the summer break the water is usually in need of a change and full of microscopic life.  Preparing a slide of a single elodea leaf, freshly picked from the water will usually reveal tiny algae, nematodes, or other single celled organisms.  A drop of cloudy water from the bottom will be full of decomposers.  If not, the elodea chloroplasts will usually show 'cytoplasmic streaming' if the students watch for long enough.

After the lab there are usually a couple of volunteers to help change the water and clean the filters.  Keeping an aquarium is a real asset to the lab. Students of all ages love the fish, so much so that my IB students pranked me with this poster on the last day of term last year.  

I have just an 60l aquarium with no heater but as the lab is warm I manage to keepa few Zebra Danios,, Neon Tetras and some Guppies in the aquarium.  I occasionally restock from my aquarium at home, and with Elodea from photosynthesis experiments.