Thanks for that and yes, I'd heard it was very difficult. Here's another - one of my little fantails, after having been fed, seems to gain rather too much buoyancy. By this I mean he tries his little heart out to reach the
bottom of the tank, gets halfway down then bobs back up like a cork !
Could this be due to the swim bladder not functioning as it should due to inbreeding, for want of a better word, in his country of origin ?