thats not the attitude to have!!! its a trial and error hobby, some things work for some tanks that may not work with others, all fis are a little different, some can be rated agressive and be completly bashful, and vice versa. you have no idea how many fish i have lost during this hobby, its probably close to a hundred (counting when i had fish as a teenager) you have just got to keep trying different things and see if they work since just last year i think i have lost i dunno maybe 20-30 fish or so, (mostly mollies platies but also some more expensive fish like my peacock eel and my violet goby) dont quit just because you experience something bad. say ok what happened, what went wrong, and see if there is an alternative that may work better.