Fish are just like people when it comes to eating.


Feed them a boring and average diet and they will lose their zest and their immune resistance will decrease…

They will live relatively shorter lives, colors will fade and behavior will become lack-lustre.

Have I got your attention yet?

Fish are what they eat, by paying attention to their diets you can get optimal coloration, behavior and immunity from your pets.

Below are some of my best #SaltwaterScientist tips for avoiding fish health problems by providing an optimal diet for your fish.

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1. Feeding fussy wild caught marine fish

This can sometimes be challenging, as newcomers to the aquarium can be fussy eaters, this is especially true for older fish which will be more “set in their ways”.

Usually this issue will be as a result of the stress of capture and acclimation to your specific aquarium conditions and will remedy itself.

The best way to deal with such fish is to mimic foods and feeding conditions as closely as possible to the fish’s natural environment.

Some species are also so fussy they are only advised for experts like Moorish Idols, which people have a lot of trouble getting to feed at all in captivity.

marine fish diet

Moorish idols are highly desirable but many specimens simply do not eat well in captivity

2. Underfeed rather than overfeed

Try to feed your fish at the same time every day this provides a healthy routine to their lives, so that they will see you coming and get all excited!

Only provide as much food as your fish can eat in a minute or so making sure that each different type of eater is catered to in terms of type of food and where you place the food for them.

Any uneaten food will breakdown into toxic ammonia and potentially throw out your water quality, you want no leftover food, it is far better to underfeed: so feed less more often.

Remember that in the wild marine life would go through periods of almost no food at all. Overfeeding is one of the key causes of crashes in biological filtration that will cause massive damage to all livestock.

Healthy diet for marine fish

Many species of Butterflyfish like this Copperband are specialist feeders which can be hard to feed in captivity. Observe the fish you want feeding in the LFS first (credit: Michael Spiller)


3. Feeding live food or not?

If you want to provide your fish a special treat by feeding live food, such as brine shrimp, ensure that you rinse under freshwater to avoid parasites and disease entering your aquarium.

Live foods are good for your fish but can be a massive effort and expense for you unless you culture them yourself.

Live foods also can make your marine life more aggressive as natural instincts from the wild come back into play.

A lot of aquarists claim live food is the much more healthy, natural option but the reality is your pets will still get the same nutrient injection from frozen foods of the same type.

However fresh foods can be a good option for new or very fussy marine fish.

Marine fish health

Corals definitely don’t appreciate uneaten food, make sure you keep this to a minimum by feeding less, more often


 4. Store prepared foods correctly

Prepared foods such as flakes and pellets can be very nutritionally complete contrary to popular belief as well as being extremely convenient.

The only issue is correct storage to ensure the food is in top condition at all times. Avoid repackaging food and buying in massive bulk, the food needs to be a quality product packaged correctly (shaker containers are good) and stored as per instructions.

If food goes off or gets contaminated it can actually kill your fish, don’t take risks here.

marine fish optimal diet

Flake that has gone off can even kill hardy fish like Clownfish


5. Frozen food is healthy and easy

Frozen foods can be purchased in convenient cubes and are actually as nutritionally beneficial as fresh foods and much more cost effective.

Frozen foods are better fed to your marine life by thawing and breaking them up in a container of aquarium water and slowly pouring in so all is eaten.

But avoid pouring in any thawed liquid from frozen food as it is usually high in phosphates and not good for your corals.


6. Vegetarian fish feeding tips

For those vegetarian species like Tangs try throwing in some lettuce and dried algae (such as Kombu and sushi Nori) from the supermarket along with their commercial foods.

Also growing algae in the aquarium from the live rock is an awesome easy feeding idea and gives the fish an element of their natural habitats.

How to feed marine aquarium fish

Feeding Tangs from a mesh bag occasionally makes feeding time more interesting for them. For more thriving aquarium tips get my free “9 success tools” ebook


A correct healthy feeding regimen is the easiest way to ensure optimal health in your marine fish. They will pay you back in spades by having more vibrant colors, behaving more naturally, being more disease resistant and living longer.

If you would like more insiders tips on avoiding mistakes and enjoying more success with your saltwater system, check out my free “Saltwater Success Tools” eBook promotion