Hi Matute!
I've done both freshwater and salt water, and frankly, saltwater has been easier for me, but definitely more expensive. Setting up is especially expensive and time-consuming.
I'm not going to tell you whether you want to do saltwater or not; instead, I'd recommend you read the...
Hi JT; I'll take a stab at it. :)
Not a happy thought.
Assuming that this means it's a 24-gallon tank, I think it might be overloaded. You did get away with it for 3 years, but fish continue growing until they die. It's possible that the hawkfish and the clowns have finally reached sizes such...
I think Brenda's right that your brown stuff is cyano, and getting rid of the rest of your bioballs will help, as well as kicking the over-feeding habit. (It's so hard not to reward the fish for the cute begging behavior!)
I can see the worm trails in the photo; sometimes bristleworms leave those, sometimes other kinds of beneficial worms. Most bristleworms are beneficial, btw: good detrivores. Best not to touch them, though. :)