The Salty Side: Saltwater Aquariums for Beginners

What Should I Feed my Saltwater Fish?

There are a lot of questions regarding what to feed your saltwater fish when first setting up a saltwater aquarium.  I know I definitely wondered what was best and when and how often to feed.  

Saltwater fish require a balanced diet so it is extremely important what you feed them and when.  

What should I feed my saltwater fish?

A varied diet will keep your fish healthy and hopefully they will live longer. 

The majority of saltwater fish keepers feed their fish frozen foods as the main source of diet.  This is because frozen foods are extremely nutritious for reef fish and are easier than feeding live foods, unless you’ve bought them.  In fact certain fish only eat frozen/live foods and will not touch pellets or flakes.

The benefits of feeding foods that are similar to what is available in the ocean, is that the fish will thrive.  They will be brighter in color, healthier with stronger immune systems.  This therefore makes them more resistant when it comes to fighting pests and diseases.  They will also be more active.

But as long as frozen foods make up the largest part of their diet, it’s not to say that you can’t also supplement feed with other foods such as pellets or flakes.  In fact, this is what a lot of saltwater aquarium keepers do. 

Getting your fish to eat pellets or flakes is also handy for when you are away on vacation and you won’t need to rely on someone being there every single day to feed your fish.

How to feed frozen food

The best way to feed your saltwater fish frozen food is by defrosting the food first in RODI water.  You can then strain it and feed your fish. 

I use a small container and a plastic sieve.  I also keep a small bottle of RO water handy in which to defrost the food.

By not thawing the food first, you risk fouling your tanks water. 

Which frozen fish food is best for saltwater fish?

There are many different types of frozen foods available so it depends what fish you have and what they prefer.  You can get anything from frozen mysis, brine shrimp, krill and blood worms to cockle, red plankton and mussels or any of these mixed together.

Remember, variety is the key to keeping happy, healthy fish.  Feeding a range of different foods will ensure that your fish will have their nutritional needs met.

Be careful not to overfeed food such as squid.  These foods are extremely fatty and too much will of it is not healthy for fish. 

How often should I feed saltwater fish?

Fish should ideally be fed a minimum of twice a day.  If you think about their natural habits in the wild, they eat small amounts throughout the day.  Sometimes this is not possible.  If you’re able to then great but the majority of fish keepers aren’t able to 

How long can saltwater fish go without eating?

I would never recommend leaving your fish for more than a few days at a time without them being fed.  If you are going away for a few days, it is worth buying an automatic fish feeder at the very least.  Ideally, you should use a feeder that feeds pellets or flakes and if going away longer than a few days, have someone come in and feed frozen foods. 

If you’re asking this question because you have a fish that is not eating, then take a look at this article. 

Can I feed my saltwater fish every other day?

In the ocean fish rarely go a day without eating something.  There is always some form of food available to them whether it be algae, small fry, zooplankton such as copepods, etc. and they pick what they can throughout the day.

The more we can replicate nature, the stronger our fish will be.  That is why fish should be fed small amounts twice a day at least, if possible.

How much should I feed my saltwater fish?

It really depends on how many fish you have.  At the moment I have:

2 x Clownfish
1 x Regal Tang
1 x Gold Rimmed Tang
4 x Chromis
1 x Royal Gramma Basslet

I feed a 3/4 cube of frozen food twice a day every day, morning and evening, as well as nori for the tangs and invertebrates once per day.  I also feed live baby brine shrimp (see here on how you can easily hatch your own) and copepods now and again.

You could also feed frozen in the morning and pellets or flakes in the evening to add a bit of variety.  The most important thing apart from what you feed, is to not over or under-feed your fish.   

The general rule of thumb is that there is food still floating around the aquarium after 2 – 3 minutes, then you are feeding too much. 

Underfeeding can result in fish that are underweight and more prone to illnesses and overfeeding leads to an excess of nutrients in your aquarium, ie. nitrates and phosphates.

Best saltwater fish food brands

There are plenty of brands to choose from!  Some brand favourites are:

Frozen Foods:
H2O Life 
PE (Piscine Energetics)Rogger’s
Reef Food
Rod’s Food
LRS (Larry’s Reef Services)
Dr. G’s

Pellets:
Hikari Marine S
New Life Spectrum

Flakes:
Ocean Nutrition 
API

Foods to take care with

Brine shrimp, unless they are baby brine shrimp, do not have large nutritional benefits to fish.  Therefore never feed your fish solely a diet of brine shrimp.  They might be good at enticing a sick or stressed fish to start eating but it should not be relied upon as a long term food source. 

Foods like squid can cause fatty liver disease if fed too often to saltwater fish.

Saltwater fish feeding times

It does depend on how many fish and invertebrates you have but the majority of reefers feed their fish twice a day.  This therefore make sense to spread this out so that one feed is in the morning and the other is in the evening.  

As mentioned previously, I feed mine small amounts of frozen food twice day, morning and evening, and nori in morning.

Feeding saltwater fish while on vacation

I have found that the best way to feed my fish when away on vacation is to use an automatic fish feeder.  And, I have someone who comes every three days to feed frozen foods and nori. 

I can’t stress how important it is to have someone you can rely on to come in every few days.  This is to not only feed the fish but to check that everything is running as it should.  There are so many things that can go wrong and they normally do … when you’re not there to sort them out.

It is also a good idea to leave the number of your local fish shop or another reefer in case you can’t be reached.  If using another reefer to help you out, this could be reciprocated when they go away. 

So there you have it!

In summary, saltwater fish should be fed a varied diet.  Frozen and live foods are best in my opinion.  Pellets and flakes can be used as a supplement but I would not recommend them as the main source of a nutrition.

Reef fish should be fed smaller amounts more often than larger amounts less often.  The more we can replicate their natural environment, the happier and healthier they will be.  

Scroll to Top