Strange Goings On In The Tank

This morning, I actually sat at the dining table to eat breakfast. I don't usually have time but today the carer was scheduled for later than usual. While eating my shredded wheat I noticed some unusual behaviour in the tank next to me, the big 180 litre.
I have a piece of redmoor wood, all spikey branches threaded with hornwort. I often see the honey gouramis inside this structure, they and the last remaining amano shrimp do a good job of keeping that white gooey algae that form on the wood under control. But this morning, all the dwarf rainbows, a couple of green neon tetras, a peacock goby and a loach were in there as well. I couldn't believe my eyes when I saw a loach swimming up one of the branches.
What on earth were they up to? The only thing I could think of was that some species or other had spawned some time between dawn and us drawing the curtains, and the fish were enjoying an egg breakfast.

Anyone have any other suggestions?

The white gooey whatever-it-is is nothing to do with the fish - I had the wood in the QT to try and soak it enough to sink, and the goo appeared in there. No fish in the QT with it.

I'll have to sneak up on the tank tomorrow as well, see what they are up to. Planning a break out?