While fish make amazing pets, they aren’t exactly known for their interactive nature. Sure, they may look attractive in a perfectly aquascaped aquarium, but for the most part, they rarely do more than swim around peacefully and maybe peck at the occasional spec of algae.

But all that changes at mealtime for the fish. They become more shameless than a hungry puppy, begging at the front of the glass, zipping around the aquarium, and basically doing anything to get your attention.

And this is the reason that many fishkeepers overfeed their fish. It’s really the only time they get to interact with their prized pet, and it can be addictive, watching them dance for you as you prepare their food.

Many fishkeepers eventually start to add an extra feeding here and there, enjoying the new-found interaction with their fish. But like many people, you’re probably thinking, what could be the harm of giving them a bit more food?

Unfortunately, the truth is that if you’re overfeeding your fish, you’re probably doing a lot of harm. The dangers of overfeeding go far beyond just ending up with an overweight fish. When you overfeed a fish, you’re putting its life at risk. And no responsible fishkeeper wants to do that.

How Much Should You Feed Your Fish?

Every fish is different and there’s no precise answer on how much to feed a fish. But if you know their diet, then it’s relatively easy to estimate how much they need to eat.

Omnivore Fish

Most fish available in the hobby are omnivores, meaning they eat both plant and animal matter. These fish should only be fed once daily and all the food should be consumed within 3-4 minutes. If all the food isn’t gone after five minutes, then you’re probably overfeeding your fish.

Sometimes, fish still seem to be hungry after the five minutes have elapsed. But that’s because most fish are opportunistic eaters. In the wild, food is often scarce and a fish will eat as much as they can catch or scavenge. The fish knows it may be hours or days until their next meal, so if they want to survive, they need to eat every chance they get.

It’s this behavior that causes problems in the aquarium. The fish quickly learns how to beg for food and to the inexperienced fishkeeper, it seems like they’re hungry and need to be fed more often. This is a vicious cycle, with the fish always fearing a scarce time, and the fishkeeper constantly feeding the fish because it seems hungry.

But don’t worry – even if you’ve been giving your fish multiple feedings a day – it will still adapt to the new feeding routine. Even the hungriest omnivore fish will be fine with being fed once a day and they’ll thank you for it later.

Herbivore Fish

When it comes to herbivore fish, feeding is a little bit different. These fish constantly graze in the wild, eating algae and plant matter. The once a day feeding regime simply won’t work as well for them. For these fish, they should be fed twice daily, with regular feedings of blanched vegetables to graze on throughout the day. But make sure to remove any uneaten vegetables after 24 hours, or they will start to foul the water. (If you want more information on feeding vegetables to fish, read How To Feed Vegetables to Fish).

Dangers of Overfeeding Fish

Overfeeding your fish can result in sick fish, algae blooms, mass die-offs, clogged filters, and dogs and cats living together (alright, maybe the last one isn’t true). But there’s no question – overfeeding your fish will give you an ugly aquarium, with sick fish, and thick mats of algae.

The first problem with overfeeding a fish, is that they often don’t eat all the offered food. The uneaten food will then settle to the bottom and start to decay. Even in a mature, fully cycled aquarium, this will often foul the water, causing a dangerous buildup of ammonia and nitrites. (Don’t know what a cycled aquarium means? Find out here.) These chemicals can injure a fish, and are why overfeeding is probably one of the biggest causes of fish loss in the hobby.

The second problem is that increased feedings, unsurprisingly, result in increased waste production from a fish. This is especially pronounced in aquariums with widebody fish like goldfish, whose only purpose in life seems to be eating and pooping. The waste and its by-products can foul the aquarium, and will often result in algae blooms – which while harmless – are extremely unattractive.

And lastly, overfeeding can directly affect the health of a fish. While rare in most species, overfeeding can result in a fish developing a fatty liver. The one species of fish that seems to suffer from this the most are bettas. This is probably because most bettas don’t have much space to move around in their aquariums, which means overfeeding is combined with lack of exercise. But it can affect any species of fish, so it’s important not to overfeed any fish.

Final Word

It’s relatively easy to correct bad feeding habits, and by properly feeding your fish, you’ll reap dividends for years through healthier fish, more attractive aquariums, and better functioning filters. So, no matter how much your fish beg, make sure you don’t overfeed them.

One of the first things that people nearly always ask me after they buy their first fish is “how much should I feed my fish?” Now you would think that this would be a simple question, but like so much else with fish, it can be more complex than it seems.

Sure, if you don’t want to do it right, you can just throw a few flakes of fish food into an aquarium and hope for the best. But if you want happy and health fish, that display brilliant colours, you need to take some time to learn how to feed your fish properly.

How Much to Feed

I wish that I could say that most people knew how much to feed their fish, but the hoards of new aquarists turning their aquarium water into foul sludge says otherwise. And let’s not even mention the grossly obese bettas out there that can’t even lift themselves out of their little ornamental arm chairs.

And it’s easy to see why people have problems with figuring out how much to feed their fish. There is no easy standard out there, and feeding fish can be a rewarding experience for people new to the hobby. Unlike other pets, the only real interaction you get with most fish is when you feed them, so many people are tempted to overfeed them.

So you end up with fish begging for food, and people happily feeding them every time the fish does a little dance near the front of the aquarium. And many fish will continue to beg for food even when they’re full (cichlids are notorious for this), so it’s often hard to tell if you’ve fed them enough.

So when it comes right down to it, how much should you feed your fish? Assuming that we’re not talking about herbivores, which like to continually graze, fish should be fed once a day and only what they can consume in 3-5 minutes. And don’t worry – you don’t have to monitor this every time. Just spend the time to watch them eat every week or two and make sure that there is no food left over after a few minutes.

Another way to look at it, is that most fish only have stomachs as large as they eyeballs. So if you’re not sure that you are feeding the right amount, you can just estimate the size of their stomach by their eyeballs, and feed them the amount that’s approximately the size of their eyeballs.

The reason that we spend so much time making sure that we don’t overfeed the fish, is that overfeeding can quickly have a negative impact on an aquarium. Not only will uneaten food start to decay and foul the water, but the fishes increased waste production can send the water parameters completely out of whack. If there is too much waste for the filter (or more accurately, beneficial bacteria) to handle, you could start to see spikes in ammonia and nitrites – both of which can kill your fish.

What to Feed

So now that you know how much to feed your fish, the next question is what to feed them? The foods for fish can really be broken down into four groups – commercial food, frozen food, live food and vegetables.

In order to keep your fish healthy and their colors at their peak, you should feed all four groups to them. Of course this is generalizing, and some fish will only eat live food, while others need a diet rich in vegetables. But for the average fish, their diet should be comprised of daily offerings of a high quality flake food, with regular feedings of live or frozen foods, and the occasional small serving of vegetables.

Commercial Food – This should be the main staple that you feed to your fish, and you should always ensure that you purchase only high quality fish foods. In the past there were many absolutely terrible fish foods, but most of the ones from larger companies (Tetra, Wardley, Newlife Spectrum) all make decent choices for your fish now. I personally use New Life Spectrum Food, and have had great success with a variety of fish.

Live Food – Live foods are by far the best foods that you can feed to your fish, and any fish that are fed live foods regularly, will in most cases be healthier and have brighter colors. That’s not to say that you should just feed one type of live food continuously, since like humans, fish require variety in their diet. Also, some live foods like blackworms can be harmful if fed too often, so make sure you research the live food type before feeding it to your fish.

Some of the best live foods that you can feed to your fish are daphnia, mosquito larvae, wingless fruit flies, gut loaded brine shrimp, copepods (may attack fry), gammarus (may eat aquatic plants), bloodworms and blackworms.

Frozen foods – Let’s face it, the average person doesn’t want to go wading into a pond to chase live food, and most people’s significant others aren’t OK with cultures of tiny worms in their basements. So an easy alternative to all that hard work is to buy frozen foods.

Frozen foods are convenient, and have all of the same nutritional value of live food. It doesn’t trigger the hunting response the same way that live foods do, but it can still make up an important component of a fishes diet.

Some of the more common frozen foods that you will find are Brine Shrimp, Bloodworms, tubifex, blackworms and daphnia.

Vegetables – It’s rare to find a fish that doesn’t occasionally indulge in some fine aquatic plant cuisine in the wild, and because of this, many of the more commonly available fish will appreciate some plants in their diet. With that being said, there are exceptions to every rule, and certain fish will ignore vegetables. So always do some research on the species of fish that you have, before you start offering them vegetables.

For the many species that do enjoy vegetables, there are certain favorites that are widely accepted by fish. These include zucchinis, cucumbers, and shelled peas. Depending on the fish, you may also experience success with other vegetables, but those should always be your starting point.

Final Word

If you follow these guidelines, and don’t over feed your fish while offering them a varied and a diet rich in nutrients, you will end up with health fish that will live for years to come. Food is one of the cornerstones of fishes health, and it will repay your effort in dividends if you take the time to do it right.