I used to have one..... I was passionate about it whilst preggers with Ickle... I had red finned sharks, the silver sharks...a big suckermouthed catfish (that I named after Ickles absent father)... some boring fish (one of which I named after Ickles absent fathers new bint)....
then I got some little tropical crabs. And came through one morning to see one sitting at the front of the tank, holding the fish named after the bint in one claw... picking bits of her out and eating it with the other claw.... the fact that it was THAT fish he was eating softened the blow a bit.
Then one of the crabs disappeared (I do not know where.... but it used to like sitting ontop of the pump).
Then after months of nuturing, and reading books and all that... one day I came home and loads of them were floating on the top of the water.... it stank.... and it all went tits up.
The suckermouth catfish survived.... I rehomed him... and sold all the kit in the local paper.
The saltwater tanks are really cool.... when its all going tickety boo.
I have just waffled like a right old anorak haven't I?