Agree with this 100%I'd say no. Food options are a lot more developed than they were 10+ years ago with plenty of options to make create varied diet - but this does require a varied diet 1-2 dry frozen foods probably doesn't cut it.
However, I have used Vita-chem in the past with freshwater fish and it does work so there probably isn't any harm in spending $15 for a bottle to see how it works and just stop after the bottle is finished if you're not seeing any benefit.