Nina7777
Fish Herder
If your only going to feed frozen food once a week or even twice a week, then one cube would be perfectly fine. I feed one cube to my 29 gallon every day which only has 5 fish in it. and I feed 3 cubes to my 55 gallon every day. so one whole cube once or twice a week will not harm anything and your fish will love it. Just make sure not to feed them anything else that day. 