How to Tell if Fish Are Hungry [Betta, Koi and Goldfish 2023]

- February 11, 2023
- Fish
- Roger Miller
Overfeeding your fish is a rookie mistake that many new fish owners make because they simply lack the knowledge on how to feed fish properly.
But, sometimes, it is quite hard to tell whether your fish are hungry or not. They will not ask you for food like dogs and cats do, and determining whether they should eat right now or later is a big problem that some of us might have.
I personally own two different tanks with fish that I love, and I have cracked the code to determine when and how to feed them.
Your Pet, Your Love will show you how to tell if fish are hungry in 4 easy ways.
Why Do Fish Always Seem Hungry?
Fish in aquariums or in the wild may seem hungry all the time because they are naturally driven to feed frequently whenever they can.
This behavior is particularly true for species of fish that are predatory or omnivorous and need to consume a significant amount of food to fuel their high metabolism and maintain their energy levels.
We can say that fish are conditioned to be hungry all the time, even if they just have enough food – that’s the way things work in the wild.
Additionally, the environment in which you keep your fish, such as the size of their tank or pond, can also play a role in their perceived hunger levels.
If the living space is too small or if the water is not properly maintained, the fish may experience stress, which can lead to an increase in their feeding behavior.
Do Fish Know When to Stop Eating?
Most fish don’t know when to stop eating, mostly if you keep them in a tank – that’s a fact supported by multiple research on fish feeding protocols.
We need to remember that fish are not the smartest pets out there. It is hard for them to know when to stop eating because they are conditioned to believe that food is limited in the wild, and, as you know, they live in a tank now, which is something that they might not comprehend.
Some fish will stop eating once they are full, but it depends on the species and the behavior of the fish.
How to Know if Fish Are Hungry 4 Ways
So, are my fish hungry? Did someone already feed them? Before we continue, it is important to mention that overfeeding fish can have a big negative impact on their health.
Fish that eat too much can face health problems that might eventually lead to death, so it is our responsibility as fish owners to ensure that our fish have a balanced diet with a properly set schedule beforehand.
1. Fish Are Stressed and Swimming Around the Tank
If you notice that your fish are swimming in odd patterns and exploring areas of the tank or aquarium that they do not usually visit, then perhaps they are hungry.
It’s like they are searching for something or looking for food in remote parts of the tank. This is one of the main behavior signs that will tell you if your fish is hungry or not.
2. Fish Are Aggressive and Fast
Fish swimming faster than normal or acting more aggressively than usual are probably really hungry and need to be fed as soon as you have a chance.
This is why it is so important for us to comprehend the normal behavior of our fish – if they are not aggressive nor fast swimmers, and then they suddenly are, it is a sign that they need food and are feeling as hungry as you do after walking your dog for two hours!
3. You Have Missed Their Feeding Schedule
If you have a properly set time of the day to feed your fish, and you miss it, they will become hungry after a while, which will lead to stress.
Although this is a sign that depends on us more than on the fish, it is a great way to know if fish are hungry.
4. If Fish Are Starving: Cannibalism
Cannibalism in fish is a reality, and research backs up this information. If you have multiple fish in a tank, and you fail to feed them for long periods of time, they will probably start to eat each other.
It depends on the species of the fish, though. Nonetheless, this is a drastic behavior that only takes place if fish are actually starving, and we must avoid this from happening at all costs.
How to Tell if My Fish Are Still Hungry
So, did you just feed your fish, but wonder if they are still hungry? There are three signs that will let you know if your fish are still hungry after feeding them:
- They wander around the surface of the tank, looking and waiting for more food to be dropped.
- They start to swim faster than normal, as if they couldn’t stay still – this is a sign that they need more food/
- You have not given them the correct portion of food, and they know it – fish are not the smartest pets around, but they surely know the portions of food that they like!

How to Tell if Fish Are Hungry by Fish Species
Different fish species will have unique behavior to show us if they are hungry or not.
The aforementioned tips help you know whether fish, in general, are hungry. But it is clear that, depending on the species, there will be other signs that you need to watch out for.
1. How to Tell if Goldfish Is Hungry
Goldfish are omnivores that can eat pretty much everything you give them, although you must obviously stick to a healthy diet, even if your Goldfish Seems Hungry All the Time!
There are three signs that your goldfish is hungry:
- They move their mouths more than usual: if you notice your little goldfish gasping for air on the surface, then they want more food!
- They increase their activity: hungry goldfish will swim around the tank and make sounds that they normally wouldn’t do if they were not hungry.
- They follow your movement: this is a primitive response to hunger that fish in the wild have as well – the goldfish identifies you as their food source, and if you are close to the tank, they will follow you until being fed.
2. How to Tell if Koi Fish Is Hungry
Koi fish usually live in big ponds with many other koi fish, which makes it a little harder to tell if they are hungry or not.
In this case, the best piece of advice we can give to you is to have a detailed schedule for feeding your koi fish.
If koi fish are hungry, they will open their mouths on the surface, swim aggressively, and even make a soft chirping noise if they see you around their ponds.
3. How to Tell if Betta Fish Is Hungry
Betta fish are carnivore fish that, in the wild, feed on insects, other fish, and small aquatic creatures.
Since betta fish are carnivores, they will have more aggressive behaviors than koi and goldfish when hungry.
Some of the signs to know if a betta fish is hungry are mouth movement, rapid swimming inside the tank, and general aggressiveness when you approach their tanks. You can learn Why Your Betta Fish is Not Eating here.
Pet Recap: How to Tell if Your Fish Is Hungry
Telling if your fish is hungry doesn’t have to be a challenge – instead of watching out for the aforementioned signals, the best thing that you can do is to have a properly set feeding schedule, regardless of the fish species you own.
If you know that you have already fed your fish, then you will never have to find out if they are hungry or not.
Bookmark this useful fish guide, and find more expert and backed up fish information here, at Your Pet, Your Love.
FAQ
Are Fish Always Hungry?
Some fish are always hungry because that’s how they have been conditioned for millennia in the wild. But this doesn’t mean that we should overfeed them – the consequences of this might be catastrophic for their health.
How Long Does It Take for a Fish to Get Hungry?
It depends on the species of fish, its metabolism, and its diet as a whole. For example, koi fish have a slower metabolism than betta fish, so betta fish will get hungry sooner than koi fish. As your veterinarian for a fish feeding schedule, so you can provide your aquatic pets with a top-notch diet to ensure their health.