An appropriate diet is important for maintaining healthy fish (and some corals). While there are many fish foods (flakes and pellets and frozen mixes) which claim to be a “staple” and contain everything needed to maintain the health of fish, the reality is that we don't know exactly what is necessary to keep fish healthy. Feeding a variety of things increases the chances that your fish will consume their essential nutritional needs. A few general tips
- The three types of foods are pellets, flakes, and frozen mixes, each with their own advantages
- It is best to use a variety rather than relying on a single product
- Do not overfeed: this is the downfall of most unmanageable tanks
- Freshness is important. Food loses its nutritional value as months go by.
- Refrigeration/freezing helps preserve food
- Avoid feeding live food except for certain circumstances
What type of Food?
Feeding a single type of fish food is extremely common but think about if you ate nothing but apples for your entire life. Now consider that those apples had been on the shelf for 6 months. Food that has been sitting on the shelf (or even in the freezer) for months often leads to fish goes bad. If fed continuously it can lead to your fish becoming nutritionally compromised and disease becomes more likely. For this reason, we recommend a variety.
As a beginner, a pelleted food from Ocean Nutrition, Tetra, or Thera spectra is fine so long as you keep it in the freezer. Higher protein on the label is in better unless you are feeding herbivorous fish. Pelleted food is perishable so avoid buying larger quantities than you will use. Read more about selecting the right pellet and how to preserve nutritional value.
Are not as clean as pellets but can be useful if your tank has fish with diverse mouth sizes. Pellets that are ideal for the larger fish may be too big for smaller fish. Read more about flakes here.
As a complement to pellets/flakes, you can add an appropriate amount of a frozen mix of food. There are many types available for purchase but avoid regular brine ship as it is practically worthless nutritionally. Brine shrimp enriched with omega or spirulina is fine. It is also possible to make your own frozen mix. Read here to learn how to make your own and to understand which frozen mixes are optimal for different fish.
How much to feed?
As a general rule, beginners tend to overfeed their fish. It does not help that fish food manufactures overstate how much food that fish need. (It is in their financial interests for you to purchase more). Overfeeding is especially easy if you are feeding multiple types of food. However, it can lead to a tank crash.
Fish need 2% body weight per day if they growing and only 0.5% body weight to stay at the status quo. It is hard to judge the right amount so a good rule of thumb is to give as much food as the fish eat in one minute. The following are indications you are feeding too much:
- There is still food after 1 minute in anything but a huge established reef tank
- You have algae problems
- There are any level of phosphates and nothing has died
- The corals aren't looking happy and your nitrate, kH, and Calcium are good.
Read more about how much to feed here