Fish tanks are actually a piece of cake to make, but you MUST use buydebug to accomplish the look. It depends on whether you want fish swimming in it or not. Basically, you make a pool and you make basement area one square away from the pool. Use moveobjectson to put windows in both the basement and the pool. The more windows the more like a fish tank/aquarium it looks. You can use buydebug to put sand piles on the bottom of the tank and in the corners. Put a table, (the one that's from the pyramids looks best), on the bottom of the pool. Go to buydebug again and buy the Fog Emitter. It looks like a turquoise blue circle. Put that on the table. By Shift clicking the FE you get a box that asks you what you want to do. You type in the command for what you want the emitter to do, and it does a LOT of things. I typed in fishsharkactive and got a nice shark swimming around! The emitter becomes invisible in live mode but you might want to disguise the table. You need an emitter for each command, so if you want more fish you need more tables and emitters. I put an emitter on the floor and no shark, BUT I could type in bubbles and get bubbles from the floor emitter. Just decorate the tank however you want to with move objects and you'll get some interesting looks. That emitter is amazing with all the things you can do with it. I'm determined to find out how to do it all.