My husband and I have had our oscar for about 2years now, he or she is in the tank with a crawfish and an algae eater. Within the past couple of months, the oscar will go around the whole tank gathering up the rocks and spitting them back out in the corner making a huge mountain. I was wondering if she (if it is in fact a female)is building a nest. I'm not sure. Does anyone know what he/she might be trying to do?

This is quite normal behavior. It is the sort of thing a breeding pair of Oscars will do. Why one Oscar still does it without a mate is unclear, it's probably just instinct as they reach sexual maturity. Oscars don't exactly make a nest, they normally lay their eggs on a flat surface, more than likely a rock that may be in your tank, or sometimes the top of a plant pot.

Welcome to our community by the way

Thank you for your response and welcoming. So under the assumption we have a female, do you think it would be a could idea to introduce another Oscar to the tank? Our current Oscar is approximately 2yrs.old.

unfortunetly both male and female will participate in the cleaning/creating of a nesting site. so for you to assume you have a female is a little premature.
as for introducing a new oscar to your tank this is something that doesnt always quite go as planned. first off you need a tank large enough to accomidate 2 oscars this means something in the 100 gallon range as well as filtration to go with it. the next obsticle will be to find an oscar of the opposite sex. this can be a challenge as well.
assuming your tank and filtration can handle another oscar and you manage to find one of the opposite sex there is no guarentee that they will breed or for that matter even like each other. it is usually a try and find out game when introducing new fish to an established tank.
hope some of this is helpfull to you......


btw welcome to the site

thanks for the info & welcoming. I never knew this site was here, wish I would have found it a long time ago.

but at least your here now and really thats all that matters..........