What you need to know about tropical fish foods

There is a plethora of fish foods available, and almost as many foods as there are fish. Here’s our handy guide on selecting the right food for your fish.

Flake or pellet?

The most popular fish food available is flake food. The vast majority of tropical fish will eat it, and it’s a complete diet, meaning that for many fish, if they had to, they could just eat flake every day for their entire lives.

Flake food starts as a floating food, which then slowly sinks as it takes on water. The advantage is that surface, mid water and bottom dwelling fish all have a chance at eating it. Big fish can be fed large flakes, and it can be crumbled up and fed to small fish. An excellent all rounder.

Pellets can be either floating or sinking, and are usually fed to large fish which can fit whole pellets into their mouths. Floating pellets take a long time to sink, if at all, so are really only for fish that will readily take them from the surface, like large cichlids and large barbs.

Sinking pellets are suitable for bottom feeding fish like catfish and loaches. Large fish will swallow them whole, grazing fish will suck on them, and small fish will pick at them too.

Sinking pellets are important for shy or nocturnal fish, and fish which won’t swim up and feed from the surface or mid water. If you have active fish swimming above the bottom dwellers, they may struggle to get any flake foods, which should normally sink down. That’s where sinking pellets come in.


Granules sink, so are suitable for mid and bottom feeders. Surface only feeders may miss them, so in those situations floating micro pellets or flake should also be fed. Granules are good for automatic feeders, and tend to be less messy than crumbled flake, which can get sucked into the filter.

Discus favour red coloured granules like Tetra Prima, and if the fish will take them, granules and pellets can be good for putting on weight, growth and body shape.  

Tablet foods

Tablets are hard, compressed food discs which can be dropped into the tank, or stuck on the glass. Few fish are large enough to eat them whole and instead they are designed for fish to suck on them and graze, like algae eating catfish, or peck at them.

Even small fish like guppies will eagerly peck at tablet foods, and having a slow release food source is good for small fish which need to feed frequently in order to maintain body weight.

Stick a tablet to the front glass, and midwater and surface feeders like tetras and gouramis will also peck at them, and having all your fish at the front glass eating from a tablet is fun to watch. 

Algae wafers

Algae wafers are vegetable based, flattened tablets which sink to the bottom of the tank. They are perfect for plecos, which would otherwise starve if they couldn’t get enough other foods. But small fish like Platies and Mollies will also graze on them, as will freshwater shrimp.

Algae based foods are good for all herbivorous fish and invertebrates.

Specialised diets

Some fish are best when fed a diet that suits their specific needs. Discus are best on high protein diets, whereas Lake Malawi mbuna cichlids are best on vegetable based foods formulated specifically for them.

Many popular fish have foods made just for them, like Siamese fighting fish, Betta splendens, and if you want to feed something different try offering Freeze dried foods, or Krill, or Bloodworm based foods. 

Treat foods are also available in stick-on tablet form, or in a nutritious gel sachet, like Tetra Fresh Delica. 

Holiday foods

New fishkeepers may worry about who would feed their fish if they went away on holiday, but there are several solutions. Automatic feeders are battery-powered food dispensers which will drop flake, pellet and granules into the tank everyday at timed intervals.

If you’re just going away for a weekend, weekend foods can be used, or slow release feeder blocks to feed your fish from three, up to 14 days, are also available. Test out an automatic feeder or holiday food block before you go away, to see if it dispenses the right amount of food, and that your fish are eating the food it offers.  


How big is a pinch of flake?

Hand and finger sizes vary, but a pinch of flake food equates to the size of a ten pence piece.

How often should I feed?

Most tropical fish should be fed little and often. This can mean two or three times per day, if the tank and filter are mature, and water quality is good. Well-fed fish grow more quickly, and are more resistant to disease. 

Can you overfeed?

Yes, the biggest problem with overfeeding is that uneaten food will cause water quality problems. Some fish can become obese, water may become cloudy, and biological filters will be put under strain, risking underlying levels of ammonia and nitrite.

Which foods do I need to get me started?

If you have a tropical community aquarium with a mix of fish, a combination of tropical flake food, sinking pellets or tablets, and algae wafers is best. That way fish from all levels and with all diets will have a chance to feed.  

How much should I feed?

Feed as much as the fish will eat within a few minutes. If there is food left on the gravel after then, you’ve fed too much and it should be scooped up with a catching net, or sucked out with a gravel vacuum.

Tablet and wafer foods are the exception however, which may take 12 hours or more before they consumed entirely. This can be handy with nocturnal or shy feeders, whereby wafers or tablets can be dropped in before lights out, and the fish can come out and feed on them after dark. 

Which is the best food for my fish?

Quality ingredients don’t come cheap, so in general, the more you pay for fish food, the better quality it will be. Species specific diets are good as they are tested and formulated specially for them, but feeding a varied diet should eliminate any risk of malnutrition, and keep feeding time interesting for the fish too.

Buy food in small amounts so that it stays fresher, and discard any dry food that gets wet in storage.    

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Jeremy Gay is an author, lifelong fishkeeper, and aquatic specialist. He's a former editor of Practical Fishkeeping Magazine, UK editor at Reefbuilders, a former aquatic store manager, and has collected fish in Sri Lanka and the Amazon. He's been on tv and radio, contributed to Koi Carp and Gardeners World magazines, been a product tester, a judge, and a product developer. Jeremy is here to guide and advise you on all things tropical, pond and marine, from set-up to stocking, health, feeding to breeding, as well as solving many common fishkeeping problems along the way.

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