Hi guys I saw a small 10 inch lungfish at my local pet store and the guy said that it should be kept alone,all of my fish are large and peaceful. So are lungfish aggressive or do they get picked on? I have a 240 gallon tank so size isn't an problem. All of my fish wouldn't be able to fit in it mouth and my marble catfish and oscar and 5 large goldfish wouldn't try to take a bite out of it. so can I get one or would there be a problem?