And lemon tetras breed really easily too. I had some lemon tetras in a tank with a pair of angelfish and lots of java moss - the floor of the tank was covered entirely with java moss - and one day I noticed little tiny lemon tetras swimming in the java moss.

I also left a bucket of water from washing the filter from one of my tanks untouched for almost a month and later found a baby lemon tetra had hatched in the water.

Makes you wonder how many times we've thrown out fertilised fish spawn when we do our water change!