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New Fish Not Eating: Reasons and Solutions

Keeping a fish pot or a fancy fish aquarium in the living room is a widely used method for home decor. The presence of colorful fish in the living room makes it appear more unique and bright. But it can give you a stressful time if you notice that your fish are not eating properly, or not eating anything at all! 

In most cases, fish stop eating because of illness or disease. Poor water conditions lead up to causing illness to your fish. Change 10-15% of your aquarium water weekly to keep your fish healthy. 

There can be other reasons for which your fish may stop eating. Here, we have tried to narrow down the most possible reasons for a fish to stop eating.

5 Possible Reasons Why Your Fish Are Not Eating

Water Condition

Bad water condition is one of the common scenarios for your fish to stop eating. Your fish does all the work (eating, swimming, peeing, pooping) in the same water. All these work change the pH balance and chemicals of the water. If the water is not changed regularly, it will eventually cause illness to your fish.


It is best to keep the temperature of the water in your tank as close to that of your fish’s natural environment as possible. The majority of freshwater and reef fish species seem to thrive in a tank that is kept between 74 and 80 degrees Fahrenheit (23 to 26.5 degrees Celsius).

Their metabolism slows down when the temperature in your fish’s aquarium falls below 74 degrees Fahrenheit (about 23 degrees Celsius).

Fish become lethargic and sluggish when their body temperature falls below its normal working level. They won’t be swimming as much and for that, they won’t feel like eating as much.

Inaccurate Lighting

Accurate lighting is an important factor to keep your fish healthy and fit. Some fish only feed in daylight. Inaccurate lighting sources will confuse such kinds of fish and prevent them from eating properly.

Food Type

The wrong type of food will cause your fish to stop eating. Make sure to feed for the right species. The trick is to combine a high-quality staple food with live foods, frozen, or freeze-dried foods a few times a week to keep their diet balanced.


If you have got all the above-mentioned factors accordingly but still notice that your fish is not eating, it is most likely it has caught some disease. 

Inspect the overall appearance of your fish regularly. Separate the one that seems ill and put it in a different tank. Separating the ill one is important as it carries a high chance of general contagion. 

There are some home remedies available that can be helpful for your fish that is ill. You can make medicated meals to treat the illness of your fish.


To make a medicated meal, you will need:

  • SeaChem MetroPlex
  • Thomas Labs Fish Bendazole
  • Maracyn 2

Heat 1/4 cup magnesium solution in the microwave and add one 1/4 ounce of plain animal-derived gelatin into the hot solution with constant stirring. Mix two teaspoons of commercial dry fish food with a small amount of the hot gelatin combination and make a paste-like consistency solution. 

After that, mix in 1/16 teaspoon of each of the three medications into the mud. Mix and mash the entire bulk in a large mixing bowl. Take a plastic sheet or a plate, spread it out into a thick pancake. Store it in the refrigerator. You can feed it to your fish for one month.

How to Properly Feed Your Fish 

There are some important factors you should consider to keep your fish well-fed. What type of fish are they, what should you feed them, how much should you feed them, and how often should you feed them?

What fish consume in nature varies depending on whether they are herbivores, carnivores, or omnivores. Their eating habits, hunger, and food availability all influence how often and how much they eat. Here are some ideas to help you supply your fish with the best possible feeding program:

Fish Type

It is important to know what type of fish you have as their food intake varies from species to species. Are they herbivores, carnivores or omnivores? 

Herbivorous fish feed throughout the day because they require a lot more plant material to meet their nutritional needs than carnivores.

Omnivorous fish have the ideal situation because they have a greater variety of food sources to choose from.

Carnivorous fish eat less food. This is because, in nature, they are less likely to catch food every day, thus their aquarium feeding schedule should reflect this.

Type of Food

Regardless of the type of fish you keep, variety is crucial. The size of the food you feed your fish should correspond to the size of their mouths.

In case of feeding frozen meals, use a turkey baster or a large syringe to distribute food a little at a time so that everyone gets some. For top feeders, squirt some food at the surface, and for mid-water and bottom feeders, gently squirt some lower into the water column.

Food Quantity

Underfeeding is always a good idea, especially in new aquariums, because uneaten food can cloud the water and cause dangerous ammonia and nitrite levels to grow. 

Feeding only what your fish can swallow in 2 to 3 minutes is a good rule of thumb. If in doubt, start with a small amount and see how quickly your fish consume it. Give them a bit more if it is consumed in less than 2 minutes.

It won’t take long for you to figure out how much food to serve them at each meal. Use a siphon hose or a net to remove any remaining food.

How Often 

Feeding your fish once or twice a day is enough. Fish that are larger and more sedentary can go longer between meals than fish that are smaller and more active. As herbivores forage all day, they need to be fed more regularly, but only in little amounts at a time.

Small active fish, such as danios and freshly hatched fry, have greater metabolic rates and need to be fed more frequently. Fish metabolisms are influenced by water temperature, which determines how often and how much they require to be fed.


Most fish feed in the early morning and late at night in nature. Although aquarium fish can be fed at any time of day, the optimal times are in the morning and evening. They rapidly figure out when it’s “eating time,” and happily swim back and forth at the surface or emerge from hiding locations in preparation for their next meal.

Make sure the aquarium light is on for at least 30 minutes before the morning feeding and 30 minutes after the evening meal. Sinking foods can be offered to nocturnal species like knife-fish, catfish, and some plecostomus shortly after the tank light is turned off at night.

Final Verdict

There are a variety of reasons why your fish aren’t eating. The majority of it can be summed up in one word: husbandry.

Every aspect of your fish’s life is influenced by its care. Water quality, lighting, food, and water temperature are all factors in fish husbandry, and any one of these can cause your fish to refuse to eat.

It’s critical to strike a balance between all of these factors while keeping fish, and the more natural it feels to your fish, the more likely they are to develop and remain healthy.


How long does it take for new fish to eat?

When placing a new fish in a tank, it should not be offered food until it has been in the tank for at least 24 hours.

Is it normal for a new fish to not eat?

It is normal for new fish to not eat as they happen to be under stress, due to the large and abrupt change in their environment.

How long can fish be without eating?

Most healthy aquarium fish can go three days to a week without eating. However, it usually is not recommended to go more than a day or two without feeding unless completely necessary.

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