How big is your axie and how big is the gravel?
Four of our axies, all 3 year olds were on gravel/pebbles prior to us buying them. Two were on glass pebbles (1.5=2cm round kind)and gravel; and the others were on 1cm fluoro coloured gravel. We've had one pair since Jan (pebble) and the others since about Mar both this year. From Day 1, with both pairs, they were pooing out gravel (we have sand so very noticeable) They still have not got rid of the gravel and its been months. Found a couple in each tank the other day.
My advice, from this experience, is to change your substrate to sand or bare tank asap. You can remove the gravel in sections and add the sand accordingly as each section is removed.
(Message edited by kapo on October 17, 2006)
(Message edited by kapo on October 17, 2006)
(Message edited by kapo on October 17, 2006)