Thanks Jim.

I just checked and it was 8 days ago I did the big water change, as I also took some pics of the tank that day.
Let's hope that this fat fiend doesn't find the fry! (pic taken on 6th April)
I was also going to post a thread about how good Cryptocoryne balansae is as a plant for river tanks, but I may as well say it here. This is a pic taken last October, not long after I planted them:
And this is what they look like now - they have gone mad and I keep having to thin them out!

Emma