I have always wanted bluegills too because I fish alot have catch them often. But they would require alot. They grow pretty big for a tank, you would need probably at least 55 gallons for 2, but thats just my guess I have never had a tank that large. Plus you would need very good filtration and still have to clean the tank often, as bluegills create lots of poop. Honestly every bluegill I have caught has pooped on me and its not pretty even small ones around 4-5" poop like a cat. So if you really want them get a big tank and be ready for lots of maintenance.