Bought

I regretted buying a niger trigger that I was told was reef safe. He was good for about 3 years and than he had a very expensive coral dinner. 10 times the cost of my most expensive meal!

 

My first saltwater aquarium. Now it seems like the spending never ends!!!

 

Probably my tang who taught me the importance of quarantining all new fish! For that matter anything wet!

 

Engineer gobies. Bought 3 juveniles on impulse about 12 years ago (they are so cute when they are small!) and did no research. Had to practically tear the tank apart a year later to get those tunneling devils out!

 

I remember thinking that some caulerpa would be nice in my tank when I first got into the hobby. I regretted that decision for years and years. It's mostly not a problem anymore, but occasionally I still see a runner coming from some unknown source just to remind me that it's still there.. Waiting..

 

I had a blue throat trigger do the exact same. It did get the chromis to school together though.. albeit in terror.