hard to keep one even w/ adding copepods very often which is crazy expensive! They could run out of copepods, their main/preferred food supply. It's best to find one that is already trained to eat frozen foods or you could take a chance, buy one and have a continuous supply of copepods and slowly introduce frozen foods in their diet. However, this takes a lot of patience/work/time.
“Success is walking from failure to failure with no loss of enthusiasm.”
- Winston Churchill