Zebra Danio's

[neven]

I currently have 2 danios left from my original three i purchased over 4 years ago, recently i raised the tank temperature and it brought it their spawning temperature. Since then one danio has stopped being the tank bully and started to patrol a small area amongst the plants at the bottom of the tank. It moves quite sharply, zipping back and forth, sometimes looking like it's trying to shake something off of it or trying to slap leaves with its body. I tried looking in to see if it was spawning behaviour, but everything i've read pretty much talked of genetics.... Also im unsure which sex each danio is. One has typically been a bit aggressive to other fishies when they swim up to the top, the other danio is mellow and just swims around.

Figured if its not spawning behaviour for danio's, its rather old age, or co2 is affecting only that fish (i'm pushing the threshhold for fishie tolerance). I do know the signs of co2 being too high for the fish, but he's not gasping, and the cardinals/black phantoms are acting normal

[Scholz]

sounds like spawning behavour to me.... My celestrail pearl danio's do a gimmy shake dance too.... and smack plants and chase the girls....