Oscar laying eggs

Question
QUESTION: I have a 75 gallon tank with 6 different types of fish.  One of them is an oscar.  Is it possible for the oscar to lay eggs if there are no other oscars in the tank and if so what are the signs that she may be going to lay eggs.  She is staying on the bottom of the tank and has dug a hole in the gravel.  She is also acting more agressive than usual.

ANSWER: Hello Doreen: what other kinds of fish do you have in the tank??? it is possible that she may be going to lay eggs or she may just be trying to make a spot that is her own and now that she has done that she is going to protect it from everyone else.... do you have places that the fish can hide?  Oscars and other cichlids like to have places that their own... in the wild they will build or find or steal rock caves, holes under logs, etc.... if she is pregnant she should be looking a bit more plump then normal... let me know...dave

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QUESTION: We have a uaru, pike, convict, jack dempsey and irredescant shark.  The oscar has been there for five months and has never done this. The oscar is about 7 inches so can't really fit in any of the stuff in the tank but it never seemed to matter until this week.  Is it possible for a different type of fish to fertilize the eggs if she lays them....thanks

Answer
Hi Doreen:  I would guess... that she is just trying to find a spot that is her own.  It could be possible that she is full of eggs but I doubt that anything  you listed could actually fertilize her eggs.  She may be fed up with the shark or the pike and after five months has decided enough is enough... welcome to the world of the Oscar... She would really like something that has a top on it... you can consider building her a rock box... or arch using large paving stones or something like that... if it turns out that she is going to spawn... keep an eye on her and your other fish because she will fight them to the death to defend even unfertilized eggs.  The thing with cichlids now is that there are so many hybridized species that its almost impossible to say if one of the other fish can fertilize her roe... I still suspect the answer to be no... but again... just keep you eye on her.  dave