Fish Food comes in a wide range to suit the different requirements/needs of your different fish and offer the variety and balance they need to ensure that your fish maintain good healthy balanced diets as they would in the wild.

Carnivores, Herbivores or Omnivores?!

Like all animals, different fish eat different things! Some are meat eaters (carnivores), some are vegetarian (herbivores) and some are both (omnivores)! Their digestive systems are designed differently to enable them to process different food and fish foods are designed to accommodate your fish’s different requirements.

When choosing your fish food, take a look at the ingredient list on the packet. As with most foods, the ingredients listed first tend to be the prime ingredients. When choosing for carnivores, make sure that the meat based proteins from aquatic animals comes first and when choosing for herbivores ensure vegetable based proteins such as soybean or spirulina are first.

Carnivores get their nutrients primarily from meats and not vegetation.
They tend to eat small fish, invertebrates and insects.

Herbivores can not usually digest meat and get their nutrients primarily from aquatic plants. They tend to ‘graze’ on live plants, seaweed and algae.

Omnivores require a mixture of meat and vegetation to get all the nutrients they require for a healthy balanced diet.

Nutritional Needs of Your Fish

As well as understanding your fish’s primary source of nutrients it is important to understand that all fish have different nutritional needs to meet their different requirements and fish foods are designed to accommodate these different needs.

Fats provide a primary source of energy, although you should avoid saturated fats and keep to “DHA” fat which is found in marine fish oil. Carnivores need <8% fat in their diet whilst Herbivores need <3%.

Proteins are required to ensure continued health and good growth. Carnivores need approx 45% protein in
their diet whilst Herbivores require 15-30% dependant on the fish.
Fry (babies) need approx 50% or more to help their growth and development.

Fibre helps to keep the fish’s digestive system healthy. Carnivores require <4% fibre whilst Herbivores require 5-10% fibre in their diets. Commercial fish foods usually contain less fibre so you may need to supplement with vegetables to assist herbivores.

Within commercially produced fish foods you will find lots of other items too used as “fillers” or to ensure that the right nutritional balance is obtained. It is useful to understand these and the affects they have on your fish:-

Moisture and Ash
As a result of the processes used in preparing fish foods you will get moisture and ash within the finished product. The greater the moisture level, the shorter the shelf life. The Ash is generally a bi-product of bone matter. Find the fish food with the lowest levels of moisture and ash content possible.

Carbohydrates
Used within the processing of fish food as binding starches. Fish don’t usually require carbohydrates to functional though sometimes whole wheat is included as ‘roughage’ to aid digestion. High levels of carbohydrates will cause serious problems to the health of your fish so lower levels are best.

Phosphorus
Fish need very small amounts of phosphorus for proper growth (less than 1%). If you have more than this, it is likely that you will have algae problems as algae consume phosphorus to grow.

Calcium
Bone and fish meals supply calcium which is important to help growth and maintain good bone and teeth health in your fish. Good fish food will contain calcium products.

Carotenoids, Krill and Spirulina
These are natural colour enhancers for fish in the wild.

Testosterone
This is sometimes added to fish foods as a colour enhancer. Often this will produce unpleasant physical behavioural issues within fish and you should try and avoid fish food with testosterone added in favour of foods with natural products such as Krill and Spirulina.

Vitamins
As with all animals, vitamins are key to maintaining great health. Vitamin A is required to assist good growth and prevent deformities. Vitamins E and A are required to maintain breeding health. Vitamins K and H are required for blood to clot and blood cells to form properly. Vitamin C is required for good digestion, bone and tooth health. Various vitamins B are required for normal growth, good digestion and overall health.

It is important to realise that a well balanced fish food will ensure your fish have a healthy life. Vitamins and nutrients are added to fish food to ensure that your fish obtain all the required nutrients that they would naturally get in the wild. Vitamin content of dried foods can quickly drop over time, so it is important to ensure that you keep smaller, fresher quantities of fish food rather than large stocks.

If you primarily feed your fish on live, frozen or freeze-dried food then vitamin additives are especially important to ensure that your fish get all the balanced nutrients they require. Vitamin additives are also a good idea at  times of stress – e.g.  when introducing fish to your tank or making big changes.

Different Types of Fish Food

So do you choose Fish Flakes, Granules, Pellets, Wafers, Gels, Liquids, Live Food or Frozen?  Such choices, but each has its place in ensuring your fish has the right food for them.

Fish with upturned mouths such as Archer fish, feed at the waters surface; fish with down-turned mouths such as Catfish forage along the ground; most other fish feed somewhere in the middle picking up lots of different floating foods as they move around your aquarium. It is best to understand what type of feeding your fish like and then buy food to suit.

Don’t forget, fish food usually comes in various sizes to suit larger, medium and smaller fish. Ensure you buy food that is of a suitable size for the size of your fish and sometimes you will need different size foods to accommodate your different size fish.


Flakes generally float and are ideal for top feeders. However, they do have the shortest retention of full vitamin and nutritional content.

Pellets and Sticks both float and sink and can be used for top feeders and mid-water feeders. They are great for fish that find the flake texture strange and are usually suited for larger fish.

Granules both float and sink and can be used for top feeders and mid-water feeders. They are great for fish that find the flake texture strange and are usually suited for smaller fish.

Wafers and Tablets usually sink and are great for bottom feeders and scavengers. They are usually designed to meet the nutrient needs of bottom feeders.

Liquids are generally used for filter feeders (e.g. Corals and Sponges). They often contain plankton and are generally used in salt water aquariums.

Gels are slow sinking and often used for mid-water feeders. They often contain medication.

Live or Frozen foods are ideal for mid-water and bottom feeders. They often incite predatory response carnivores.

Live and Frozen Foods

Some fish will only accept live food, particularly marine fish. Live food is also turned to when ‘picky’ fish fail to eat other forms of fish food.

Often live food brings out the prefatory response in carnivores that other dried foods can’t due to the movement live food bring to the water. Live food can often be difficult to obtain and it is often thought ‘cruel’ to feed with some live foods. Please be aware when introducing live foods to your aquarium as they can often carry parasites, fungi or bacteria that could contaminate your aquarium. Most people tend to not use live food unless they have a trusted source and feed frozen food instead.

There are many high quality frozen foods available which can be served on a feeding prong and moved within the water to create a ‘live’ effect to entice predator like behaviours. Alternatively, just defrost and place in your aquarium like any other food and allow gravity to create the movement. Ensure you have chopped some of the food up into smaller pieces so your smaller fish get a share of the food.

How Much and How Often

Herbivores are natural grazers / nibblers and usually have small stomachs. As a result, they tend to eat little and often throughout the day grazing on plants and algae or anything else available. Hang a lettuce leaf into your tank and watch them graze on this during the day! Herbivores and Omnivores should therefore be fed a small portion of food once a day. They should be fed enough food that they can consume within 3 minutes and after this time; you should remove any excess that remains using a siphon or a net.


Carnivores prefer a feast! They have larger stomachs and often will eat one large meal that will digest over a few days. Carnivores should be fed every other day (or say 3 times per week) and the same 3 minute rule should be applied.

Fry and young fish will need frequent feeding of protein rich foods to help them grow strong.

Bottom-feeders sometime miss out. You need to ensure that your bottom-feeders get sufficient food and you may need to distract the top and  middle feeders to ensure sufficient food reaches the bottom-feeders. One way is to place floating and slow sinking foods into your aquarium first and then, after a couple of minutes, drop in the sinking wafers or tablets. Once food has reached the bottom, the same 3 minute rule should apply.

Corals, Sponges and filter feeders that rely on liquid diets should be fed phytoplankton during the day and zooplankton at night. Ensure that you turn off protein skimmers when feeding plankton.

Nocturnal fish , such as Catfish, need to be fed at night. This is to mimic their natural nocturnal behaviour and could be done a little after turning off your tank day lights.

Over feeding is a common and harmful activity. If is more harmful than underfeeding. Most fish will survive a few days without feeding as they would in the wild when food sources are sometimes scarce. Overfeeding will lead to quick pollution of your aquarium making it appears dirtier but more importantly, increase the ammonia levels as excess food breaks down.

It is important therefore to keep your feeding to the right level and if you see your ammonia levels increasing then overfeeding may be a cause. Do not allow excess food to remain in your aquarium as this will decay and get caught in your gravel or decorations within your aquarium and continue o affect your water quality.

If you are going on holiday, you may wish to consider an automatic fish feeder for use whilst you are away as neighbours, friends or relatives that come and feed your fish whilst you’re away do have a tendency to over feed! If you do get someone to come in and feed you fish, perhaps you could pre make ‘portions’ of food they could use on set days/visits, thus helping toe ensure your fish are not overfed. Another alternative is time release food blocks. The quality of these is improving and they may be suitable alternatives for you when on holiday.

Summary
A varied diet is very important to all animals – your fish included! Like us, they will like the odd ‘treat’ along with their main meals. This will replicate the experiences from their natural environment where they will eat different foods at different times.

The variety of food given to your fish will ensure that they receive all the nutrients they require from a varied diet and ensure your fish remain as healthy as possible, be vibrant in colour and remain full of energy giving you much enjoyment from your aquarium.