Hi I live in Australia and tilapia are an obnoxious pest just like our cane toads. They have infiltrated our waterways and are a threat to our native fish. If we are caught with one of these fish we will be fined $50,000.00. So it may be the same in other countries. My son caught one down the creek many years ago and brought it home, unbeknown to me it was a tilapia. We had him in an aquarium for 10 years. When we did find out what he was it was heart breaking to think we had to destroy him. We called him George and he was the best fish we ever owned. He didn't bother the native rainbows or guppies that inhabited the same tank. He was gentle inquisitive and tough. It didn't matter what his water condition was like. The reason they can inhabit our waters is because of their toughness. They are mouth brooders and their survival rate is very high. They can live in very shallow water, very dirty muddy water and have been known to tolerate salt water therefore allowing them to migrate to further places and they live a long time. They are not the prettiest fish to look at but we loved our George. But yes please don't have one if its going to get you in trouble. Bev.