I bought 2 orandas to add to my tank on Friday,the one has adapted very well and is very sociable with my other 2 existing ones.i am concerned about the other one as he hides all the time,either behind the filter,or in the crevices of a rock in the tank.he comes out very occasionally to feed,then disappears again.from what I can see he looks a bit bloated,is this normal behaviour?im thinking maybe he is constipated or is he just shy? I can't get a proper look at him as he's always disapearing.hence I have named him Houdini .would be grateful for any advice.im worried that he is diseased and that it will spread to my other 3 seeming healthy orandas.