I went fishing yesterday to these pond and in one of my fishing spots there was a big school of tilapia just swimming back and forth. When this happens should i fish right in the middle of the school or try in other spot or what????

Tilapia can spawn something like 5 times a year.  When they do they become very territorial and will not tolerate bass near their bedding area.  If they are grouping they may be in their initial rituals.  Did it happen early around dawn?  They will group up as the plankton rises or sinks from the surface and plow the surface with gapping mouths gulping up their fill.  Look for new water, wherever they come, soon will be in ruin!

Interesting to note that the "tilapia" is a generalized term for over 90 species of cichid. The tilapia filets you buy in the store can be a mixture of any of them! An evening news cast had a segment on this not too long ago. Similar to the term "scrod" here in the northeast, which can many different species of white fish.