Feed your saltwater fish in a way you can be proud of. Increase health color and longevity

The challenge you face when learning how to feed your fish, the right way, is two-fold. First, you want to get them the right nutrition but overdoing it will cause all sorts of problems by elevating waste levels. The trick is finding the balance and we will show you how to get there.

Bulk Reef Supply Preferred Fish Food Mix

Choosing The Right Fish Food

None of the fish we selected so far have really complex nutritive needs and almost any marine fish food will keep them alive. Our goal is more than that, however, we want our new pets to live healthy and thriving. If treated right, some of these fish can be with you for decades, longer than most any other pets in fact.

A combination of high-quality foods is your best approach. We are using TDO Chroma Boost, Hikari Seaweed Extreme and PE Frozen Mysis Shrimp in tanks here at our office. These foods fill the four requirements we have established for a healthy fish diet - nutritive content, similarity to a natural diet, coloration and nutritive density.

PE Mysis Shrimp nutritive content

Nutritive Content - This refers to the fat and protein content of the food. Protein is what the fish will use to build muscle tissue and fat is one of the primary sources of energy. Almost every pack of food will have protein and fat content listed right on the label.

A quality dry food (flakes and pellets) should have 50% protein and fat content somewhere in the teens. Frozen foods contain a lot of water weight and high-quality frozen food will contain about 12% protein and 2+% fat content.

Natural Diet - Similarity to the fish’s natural diet is important and it means the food’s primary ingredients are aquatic-based; NOT corn, soy, fruits or terrestrial animals. These aquatic-based ingredients are often listed on the label and will be things like Mysis shrimp, clams, muscles, octopus, shrimp, crab and a variety of other seafood.

You also want to incorporate things that these fish naturally eat, for example, Tangs eat a lot of algae so incorporating this into their diet is crucial for long term health and likely also basic metabolic function. Frozen foods generally fill this niche but can also come in the way of dried seaweed or pellets like the Hikari Seaweed Extreme.

Brilliantly colored fish in a reef tank

Coloration - Many fish can not synthesize desirable color pigments on their own, at least not in the quantity desired by reef aquarists. The addition of green and red nutritive pigments via diet is a very effective way of really getting impressive colors to show. In our case, we are providing it primarily with the red astaxanthin content found in the TDS Chroma Boost pellets and green pigments in the Seaweed Extreme.

Nutritive Density - Pellets are about 5-10 times as nutrient-dense by weight as frozen foods. Meaning they can eat much less to get the same nutrition but that also means it is 5-10 times as easy to overfeed pellets as frozen food. Maybe even worse because pellets are kept at the tank and tempt us to feed all the time, whereas frozen foods require us to go to the freezer first.

The net overall effect here is feeding a mix of foods that considers all of these needs. An effective approach is to feed frozen food one day, then feed dry pellets the next day and continue that pattern.

Feeding Ring

How Much Is Too Much?

Getting the right amount can be tricky. Take the amount you think you want to feed and cut that down by about 80% and you will likely be closer to the right amount. It is a very tiny amount because fish are small, with even smaller bellies.

Using a feeding ring is a great tool to keep food out of your filtration. It gives the food time to hydrate and slowly sink so the fish can get it before it gets lost in your tank.

Nuisance Algae

If you find yourself overfeeding, all that extra food is going to break down into nitrate and phosphate in the tank. Nitrate and phosphate are essentially plant fertilizers so they fuel undesirable algae growth. Algae growth and continually rising nitrate and phosphate levels are sure-fire signs of overfeeding.

In new tanks, most people shoot for nitrate levels ranging 2 - 5 PPM and phosphate levels from 0.1 - 0.2 ppm but remember, it is more about keeping your number stable than it is about shooting for a specific range. So long as the nitrate and phosphate are not continually rising, you are on the right track.


The answer to overfeeding is simple, feed less. If you really prefer to feed heavily, simply understand more frequent water changes or turbocharged filtration will be required to keep the tank healthy and remove all of that extra waste. Protein skimmers, refugiums, filter socks and automatic filter rollers are all effective means of keeping waste levels under control.

While shopping for food, it is a good idea to pick up a phosphate and nitrate test kit. The Hanna Instruments Phosphate Checker is by far the most popular option for monitoring phosphates because it is just easy to use when testing very low levels and the Nyos brand test kit is the easiest to perform nitrate kit.

What’s Next?

It’s been a long wait but it is time for corals! In our next episode, we talk about adding your very first corals and give you a full rundown of what to watch out for when buying them.

5 Minute Saltwater Aquarium Guide Episode #18

Looking for a different topic or have questions? You can binge the entire 5 Minute Saltwater Aquarium Guide playlist right here on our website. We also invite you to join the #askBRStv Facebook Group which is a free resource for you to ask questions, get advice, interact with other hobbyists and get your daily reef aquarium fix.

← Previous Next →