If it's a Nile Tilapia, get ready. I bought some bait fish while fishing once, took one of the little boogers home and put it into my 75 gallon Cichlid tank. That little sucker grew so fast, and developed a nasty temper. I did some research, come to find out it was a Nile Tilapia/Perch. They get really big too, you may want to release it, or have a really large tank and really large tank mates that can handle themselves.