I, like most hobbyists, LOVE to see my fish well-fed and happy!

In addition to feeding a variety of different foods (including pellets, flakes, frozen foods and seaweed), I also soak my food in liquid supplements to maximize the nutrition of the food I am feeding. 

Feeding a variety of high-quality foods helps keep fish alive and healthy. The addition of extra supplements enhances coloration, helps fish recover more easily from stress and boosts overall health/immunity. Additionally, proper nutrition helps tangs and angelfish fight off and even reverse the dreaded HLLE (head and lateral line erosion).
The daily feeding frenzy!
Here are three great products I use:
  1. Vitamin Supplement: Continuum Aquatics Bio-VivM. Similar to One-A-Day Vitamins for people. The Bio-Viv M is a multi-vitamin additive that helps to fortify food and boost its nutritional value.
  2. HUFA Supplement: Continuum Aquatics Bio-VivHUFA. These supplements provide essential Omega-3 fatty acids (including DHA and EPA) required for growth and development. Some of the food will contain small amounts of HUFA, but usually not in sufficient concentrations.
  3. Garlic Supplement: Continuum Aquatics Bio-VivGarlic. Fish seem to LOVE garlic. It is great for helping finicky fish to eat and makes food extra tasty. Supplementing food with garlic has also been observed to help fish fight off external parasites.
If you are soaking dry pellets, flakes or seaweed, simply soak the food for 10-15 minutes then pour the entire contents to your tank. A little goes a long way so you don't need to use too much.
For frozen foods, allow the food to thaw in the supplement mixture for 30 minutes. Since I am pretty diligent with water changes, what I do next is add in some seaweed flakes to soak up the excess liquid. Since the excess liquid is high in organics, I only recommend doing this if you have very low nitrate/phosphate levels. Usually what you'll want to do is to strain out excess liquid with a fine fish net before putting the food into your aquarium.

I typically feed dry foods once or twice daily and frozen twice weekly. Having this feeding regimen (versus feeding frozen foods everyday) allows me to keep a good balance between having the fish well-fed and maintaining good water quality. The benefit of increased vitality and disease-resistance definitely make adding these food supplements a worthwhile step!