Obesity in Aquarium Fish: Are You Overfeeding Your Fish?

After days and nights of snacking on unhealthy junks, we notice a couple of pounds creeping here and there in our bodies. After gaining some pounds, we rely on Google for ideas. We swap our foods from junk to healthy; we try out intermittent fasting, we start exercising and choose all the healthy options that the websites have to offer to get in shape. However, this article is not about us; it’s about a peculiar topic: Obesity in aquarium fish.

While I was indulging a slice of rich, creamy, and moist chocolate cake and also searching for tips to stay healthy on Google at the same time, a thought crossed my mind. I wondered if people knew about obesity in aquarium fish. So, I decided why not write an article about it. If you have fish companions at your home, this article will let you know more about their health.

Can Fish Get Obese?

Yes. Fish can also get obese. The reason is their diet. Fish indeed get fat right after having a big meal, and some fish are naturally chubbier. However, you can witness obesity in fish if you overfeed them. I know some of us can’t stop feeding our pets quite often, even if they aren’t hungry. This is our way of showing love to them, but it can also be a matter of concern.

Sometimes, fish tend to look bigger because of several reasons. It might not always be due to obesity. People often confuse obesity in aquarium fish with other fish diseases. To be precise, your fish may look chubby from outside; however, there may be other issues inside your fish’s body rather than just fat mass.

Bloating or Obesity in Fish?

Does your fish have a swollen abdomen? Now, you might mistake bloating for obesity in aquarium fish. I can’t blame you for this because this syndrome looks as if your fish is getting obese. Bloating is caused by bacterial, viral, or parasitical infections. This condition is usually seen in a stressed fish having a weak immune system.

Observe whether your sick fish’s scales are standing out on end or not. If your pet is lethargic, having trouble breathing, appetite loss, red marks on the body, and excreting stringy, white feces, then these are the signs of bloating.

How to Fix Bloat in Fish?

  • The first thing to do is quarantine your sick fish to prevent it from spreading on other fish.
  • The next primary step is to do a 50% water change of the aquarium. Add one tablespoon of aquarium salt for every 5 gallons of water.
  • Help reduce its stress by dimming the light and keeping it in a breeder box.
  • Don’t feed your fish for at least three days. This might be hard for you, but it’s for the well-being of your beloved fish. Feed your pet as soon as it starts making some progress.
  • Anti-bacterial medications such as Erythromycin for gram-positive bacteria and Doxycycline for gram-negative bacteria

Tumors or Obesity in Fish?

Unfortunately, fish aren’t immune to tumors and cancers just like us as well as other animals. Fish get tumors due to a viral infection or due to the genes. The location of the bumps or lumps of tumors can differ in each fish. The tumor can be found in the gills of fish caused by thyroid dysfunction. This tumor can be detected when the fish cannot close its gills normally.

On the contrary, the tumor in the reproductive organs of fish is quite tricky to identify. This internal tumor causes its abdomen to swell, which looks exactly like the abdomen of an overfed fish. Loss of appetite and inability to swim are some of the symptoms of tumors. I am sorry to say, but the tumor shows symptoms quite late, which makes it impossible for you to save your fish.

Pregnant or Obesity in Fish?

If your fish is a female and it has a swollen belly, congratulations! Your tiny pet might be pregnant. There’s no need to worry because your fish’s abdomen may be filled with eggs rather than fat masses. To make sure that your fish is pregnant, check out whether it displays the following signs.

Signs of Pregnancy in Fish

  • The gravid spot at the back of the fish grows larger and nearly black when its eggs have fertilized.
  • The fish appears to be healthy.
  • Have difficulty in swimming due to the weight of its eggs.
  • Loss of appetite when the delivery time is near.
  • Hiding or searching for the right place to deliver eggs.

When it comes to pregnancy in fish, you don’t have to do anything extra. Just feed your fish with the right amount of high-quality foods on time. Keep calm and have patience because your fish will be fine.

Dropsy or Obesity in Fish?

Another reason for a fish to have a swollen belly is dropsy. Dropsy is a tropical fish disease which is caused by bacteria Aeromonas. The water and other fluids accumulate along with the tissues and body cavities of the affected fish, giving them a pinecone appearance, and its scales stand out. Pale gills, swollen anus, stringy feces, loss of appetite, and lethargy are the symptoms of dropsy in a fish.

To treat your sick fish, provide enough care by following the steps below.

  • Quarantine your sick fish.
  • Change the aquarium water frequently and add 1 tablespoon of aquarium salt for every 5 gallons of water.
  • Feed your fish with the right amount of good-quality foods.
  • Add anti-bacterial medications such as API Melafix as prescribed.

Are You Overfeeding Your Fish?

Now that we have cleared all the confusion, let’s hop on to the real deal:- Obesity in aquarium fish. It sounds bizarre, but it is 100% correct. I am specifically stating about aquarium fish because obesity is rare among the fish in the wild. You can assume that nature itself is a dietician for the fish in the wild. Why? Since food is limited in the fish’s natural surroundings, sometimes they have to stay for 2-3 days without having any meal. As a consequence of this, the fish store fat deposits to survive without meals. However, that’s not the case for the aquarium fish.

The diet you give to your fish is the cause of obesity. It depends on what kind of, how often, and how much food you provide to your fish. As I mentioned earlier that it’s hard to distinguish between a chubby fish and a bloated fish by looks alone, you might want to know how to find out if your fish is becoming obese by overeating.

Signs That You Are Overfeeding Your Fish

I agree that feeding is the most intimate way of interacting with your fish. When you approach them, these lively creatures expect you to shower them with love i.e., food. You think what harm will a little sprinkle of food do anyway, and you’ll give them food each time you get near the fish tank. The result is obesity in fish. Here are the signs that show you are overfeeding your fish.

Leftover food

Fish eat promptly after dropping the food in the tank. If there are still some leftovers after five minutes, this is a sign that you are giving away too much food to your fish than required. In our case, we would have already kept the leftovers in the fridge. Fish can’t do that, so go ahead and scoop all the uneaten food before it contaminates the tank water.


Another visible sign of overfeeding your fish is the dirty green or brown algae that cover the surface of the fish tank. That means you are not just taking care of your fish but feeding the algae as well. Algae consume food just like other plants, and the leftovers having good nutrients will help it grow in excess.

Excess feces

The more you feed your fish, the more they will excrete. So, when you see strings of feces attached in your fish’s bodies, note that it is the result of your overfeeding habit.


Smell your aquarium. Why are you scrunching your face? Does it smell that bad? Well, this means that the rotten leftovers, excess feces, and the bacteria together have shown their filthy magic.

Residue on The Substrate

Apart from feeding your fish along with the algae, where will the leftovers go? These will sink to the bottom of the tank if you don’t scoop on time. The food decomposes between the pebbles which your fish may try to consume.

Unhealthy Fish

All the signs mentioned above will degrade the quality of water, thus making you fish prone to fish diseases.

Can Obesity Kill Fish?

Overweight can cause multiple health complications in human beings. It can cut off years of your life. The same happens to your fish as well. Even without having any sort of gastrointestinal problem, obesity can gradually kill your fish.

Obesity in Fish is an Issue

Fish seem to be hungry all the time. These creatures have no limit on consuming food, so they’ll eat whenever you give them. No matter how healthy the food is, it will affect your fish’s health if given in excess. Remember that obesity in fish can have severe outcomes. Due to the consequences, you might lose your fish.

Avoid Overfeeding Your Fish: Tips 101

You can’t even imagine taking your fish to the gym. Plan a strict diet routine for your fish instead. You must have noticed that fish beg for food whenever they see you, and you being a warm-hearted person, can’t resist yourself from feeding them. Of course, you want your fish to live longer, don’t you? So, you have to suppress the desire to feed and walk away for the sake of curing obesity in the aquarium fish.

It’s time to get your fish back in shape, and the transformation starts from you. First of all, you have to vow to stick to the plan and indulge in the hygienic habits for the sake of your fish. Here are the tips that can help you to form a diet routine for your fish.

Time Table For Your Fish

Stop feeding your fish 5-6 times a day. Your fish will do great if fed twice a day. If you have the urge to feed your fish frequently, then feed your fish in an extremely small quantity each time.

Reduce Food Portions

Avoid adding a large amount of food at the same time. First, sprinkle a tiny amount of food and see if your fish eat up all the food. If they do, then add some more. Make sure their eating session finishes in less than 5 minutes so that they don’t overeat.

Quality of Food

The wrong type of food can also cause obesity in fish. Nutrition-rich foods are essential for your fish’s overall health. Fish foods from shops have chemical preservatives, and if you think they are expensive, you can swap their foods. Read this article till the end to find out the food swaps for your fish, which are equally high in nutrients and minerals.

Frequent Water Changes

Even if you’ve given the right amount of food to your fish, there might be few chunks of uneaten food in the aquarium. So, change the water once a week to create a hygienic environment for your fish.

Fish Food Swaps

You can always opt for home-made foods to feed your fish. We want the best for our pets, and sometimes we like to go the extra mile and make food for them. When it comes to making food for fish at home, the advantage is you can use the best ingredients. You can save a lot of money as well. Plus, you can cherish the joy of feeding your pet with the food that you made yourself. Here’s the list of foods suitable for both herbivores and carnivores.

  • Lettuce and spinach
  • Boiled rice
  • Earthworms
  • Green peas
  • Frozen foods
  • Sprouts
  • Fresh seafood
  • Raw eggs
  • Spirulina
  • Fruits
  • Broccoli and carrots

All You Need To Know About Your Fish

Check out some of the FAQs to know more about your cherished fish companions.

How Often Should You Feed Aquarium Fish?

It depends on the kind of fish you have. Fish can digest the food completely in 16-24 hours. So, once or twice a day is enough for feeding your fish. If you have vegetarian fish, provide them with small chunks of food or live plants frequently. Nocturnal fish should be fed right before you go to bed. The newly hatched fry need even more feedings. So, feed them with special foods for fry.

How Long Can Fish Survive Without Food in an Aquarium?

Are you planning your holiday? But, you don’t want to leave your darling fish behind. The good news is your fish can do well, even in your absence. You can leave your fish for 2-3 days without any food preparation. However, if you are leaving your town for a week or more, then you need to consider a few things.

Ensure that your aquarium is old and well-established. Clean the filtration system and change 50% of the aquarium water two days before leaving. Also, if you don’t want to leave your fish hungry, you can use an automatic feeder to feed your fish while you are away from home.

A healthy adult fish can survive for a week without food since it uses adequate fat mass reserved in its body. This is not the case for a fish fry, as they need to eat several times a day.

Do Fish Get Bored In An Aquarium?

Yes, When it’s so hard to predict a human’s emotion, you might get overwhelmed to know that fish also have emotions, and it’s scientifically proven. I mean, you can’t compare the experience of being under the delightful sea with the aquarium water. So, they might get bored sometimes. Otherwise, the jolly fish jump and explore their aquarium most of the time. Nonetheless, if you fail to satisfy certain needs of your fish, then the fish may behave weirdly.

How Do You Know If Your Fish Are Happy?

Healthy fish are happy fish. You can’t ignore the radiance on the skin of your fish every once in a while. That’s when you know your fish is happy. These vibrant species swim back and forth freely with more energy when they are happy. Happy fish breathe normally and love to eat.

Can Fish Die From Loneliness?

Fish do get lonely, and they can die from loneliness. Schooling fish are social in the wild, so they enjoy being in groups even in the aquarium. It is difficult for them to survive alone; that’s why professional aquarists prefer to buy fish in pairs rather than just one. After all, your companion needs a look-alike companion too.

Can Obesity in Aquarium Fish Cause Constipation?

Overfeeding your fish with poor quality foods can cause constipation, and the evidence is stringy, slimy, and pale feces. To cure this, offer a small number of peas, baby brine, or daphnia twice a day for the time being. This will do the work.

Is Bread Bad For Fish?

Yes, bread is bad for fish as it contains yeast, which is not good for their digestive system.

Preventing Obesity in Fish

It’s better to prevent obesity in the aquarium fish than cure it. Feeding doesn’t have to be the only way to show your affection. You already do tons of things to care for your fish. That doesn’t mean you should starve your fish. Just make sure you don’t turn your fish into inflated balloons. Don’t let your method of interaction become the reason for your fish’s death.


Image Credit:

  • https://en.wikipedia.org/wiki/en:Creative_Commons [Modification Made]