okay so i have a pair of convicts that i got about a month ago when i started my tank. i have them then a bumblebee cichlid, a peacock cichlid, and 2 jack dempseys(sry if not spelling that right) so i was wondering how come im not seeing any eggs in the tank. they have dug a pretty bit hole in the rocks all the way down to the glass and they are guarding it like carzy but i see no eggs. this isnt the first time this has happened. about 2 weeks ago they done the same thing except in a different part of the tank but i still have yet to seen any eggs. do u think its because they dont have enough room cause i have to small of a tank (currently have a forty gallon tank..working on getting another one for the convicts. amazingly enough everyone gets along contrary to what i have read) or do u think something is wrong with either the male of the female?? im new to this so im not sure how it works. any help would be much appreciated

thanks