Fish Laying at The Bottom of the Tank- Possible Reasons

Fish Laying at The Bottom of the Tank- Possible Reasons

Are you wondering why your fish usually lay at the bottom of the tank?

We love to see our little homies swirling and dancing in the tank, but sometimes their behavior seems weird. It is when understanding whether this habit is normal or you need to intervene helps.

You may find your fish spending most of its time lying at the bottom of the tank. While this is usually not a matter of concern, it could indicate a serious issue that you need to work on. This article will discuss the non-concerning, concerning, and abnormal behavior that fish may show when lying at the tank’s bottom.

Fish laying at the bottom- Non-concerning Reasons 

For many fish species, spending most of their time at the bottom of the tank is normal. Such fish are termed bottom dwellers. Likewise, some fish love resting at the bottom while others may get too old to swim energetically all through the tank all the time and, thus, prefer the bottom.

Let’s understand each of these reasons in detail.

  1. Bottom dwellers– Fish that spend most of their active hours near the bottom as their behavioural pattern are bottom dwellers. Some examples are loaches, plecos, cory catfish, etc., which you will see more inclined toward the lower parts of the tank.
  2. Bottom feeders– The terms bottom dwellers and bottom feeders are often used interchangeably. You can find such fish dwelling at the bottom in search of food. As you feed the fish and it sinks to the bottom, these fish gulp it instantly or scavenge for leftovers in the gravel.
  3. Resting– Most of the fish varieties prefer resting at the tank’s bottom. You may also see a fish sleeping peacefully and misunderstand it as being dead. Energetic fish fall under this category and often go to the bottom to rest in between their active and energetic sessions. If you have more such fish in the tank, try to keep cave-like décor at the bottom where fish can hide and rest. Likewise, you may maintain a schedule to keep the aquarium lights on and off that encourages fish to rest.
  4. Age– Aging and old fish tend to rest more than those who are in their active phase. The normal lifespan of fish is around 3 to 5 years, and as they proceed towards the last phase, they tend to rest more and thus dwell at the bottom.
  5. Newcomers– Every new fish you introduce will first look for the places to hide. If there is no refuge in the aquascape, dwelling at the bottom and hiding between the plants will come to their rescue.

However, they won’t show this behavior for long and start exploring once they get adjusted to the tankmates.


Fish laying at the bottom- Concerning Reasons 

If you are experiencing some behavioral changes in your fish and now it is found more at the bottom, it’s concerning. Here are the possible reasons that you need to take an action on-

  1. Getting bullied or harassed  

When a fish, which is typically a surface feeder or mid-level swimmer, starts laying more at the bottom, it indicates that it is being harassed or nipped by some tankmates. Due to this bullying, it is taking the resort of bottom. In such cases, you need to find out the harasser by watching the fish behaviour. If bullying continues, you need to remove the harasser from the tank and find compatible tankmates.

  1. Overcrowding

Often, beginners overstock their tank by introducing more fish in a small tank. In the quest to make their tank look lively, they keep introducing more and more new fish, which end up in overcrowding. At the same time, having too many fish with the same swelling level also creates such a problem.

The solutions to this problem are-

  • Prevent overcrowding
  • Get a large tank
  • Find compatible tankmates
  • Introduce a mix of fish- surface to bottom swimmers
  1. Territorial behaviour 

Some fish have territorial behaviour wherein they start to claim the bottom as their territory. If you witness more fights at the bottom of the tank, the possible reason is some fish species is struggling for territory and thus showing the aggression.

If you have aggressively behaving fish species, get a large tank where they can claim their territory without being violent to other tankmates. At the same time, you can section your tank by creating an aquascape with the help of plants of varying sizes. It will allow fish to claim their territory in a particular section without hampering others.

  1. Water temperature 

It plays a crucial role in deciding fish’s behaviour. If tank’s temperature is not within the range and drops too low, fish may lay at the bottom motionless. It will help it to conserve its energy. Similarly, if the temperature goes too high, only the bottom of the tank will have high oxygen for the fish to survive, dragging them to lay there.

Improper water temperature can lead to a number of issues and drastic results. Therefore, maintaining proper temperature is a prerequisite for keeping an aquarium.

  1. Poor water quality 

When the water temperature gets out of range, the overall water quality drops and fish start behaving disoriented. While sensitive fish are more prone to getting diseases and tends to get fungal, bacterial and parasitic infections easily, hardy fish goes to the bottom of the tank as a survival instinct.

In such a case, first of all, the water parameters should be checked using a reliable aquarium test kit. Look for the parameters like pH, ammonia, nitrite and nitrate, along with temperature. If any of these come out of range, and maintain their right level. Try to keep them constant rather than fluctuating.

  1. Strong water flow

If the fish seems to be struggling to swim and maintain its position, it indicates that the water current is too strong for it to handle and is tiring it out. In such cases, fish stay at the bottom to escape the hard currents, which makes them exhausted.

If that’s the reason, you need to adjust the filter flow rate. Reduce the flow and find the optimal setting for the tank. You can also do the following-

  • Use a pump with adjustable control
  • Instead of one big filter, install several small filters with a low water flow rate
  • Keep décor items strategically to divert water flow

Fish laying at the bottom- Possible Diseases

Fish may get a number of diseases due to varying reasons. Poor water quality, poor diet, stress, etc., all can trigger a disease outbreak. Likewise, introducing new fish without keeping them in a quarantine tank also increases the chances of disease infestation.

One of the telltale signs of diseases among fish is lying at the bottom. Sometimes, it’s a survival instinct, while other times, it’s a symptom. Here are the common fish diseases that can compel fish to dwell at the bottom-

  1. Ammonia Poisoning 

As the name indicates, excess ammonia in the tank leads to ammonia poisoning. It is a life-threatening disease for fish but is often overlooked. Therefore, keeping an eye on the ammonia and nitrite levels is crucial.

It usually happens when the tank is overcrowded, and the fish are overfed. All this led to the accumulation of more excreta and, thus, more ammonia and nitrite in the tank.

If you witness more and more fish start laying at the bottom suddenly, it is highly likely that it is due to ammonia poisoning. Other signs of the disease include difficulty breathing and loss of appetite.

  1. Swim bladder infection 

Fish’s bladder (gas-filled organ in the body) helps them stay buoyant in the water. While healthy bladder allows fish to float in water with no hassle, fish with swim bladder infection loss buoyancy and as a result, lay at the bottom of the tank often.

If you find your fish struggling to swim, trying to swim only at the surface, or sinking to the bottom, it could be because of swim bladder disease. The common causes of the disease are poor water quality, overeating, digestive issues, kidney malfunction, and secondary bacterial infections.

  1. White spot disease

It is a parasitic disease, also called ich, and is caused by ciliated parasites (Ichthyophthirius multifiliis). One of the prominent telltale signs of the disease is the appearance of white spots on the body. Other symptoms include-

  • Laying at the bottom
  • Rubbing against rough surfaces
  • Erratic swimming
  • Lack of appetite
  • Signs of distress

Malnutrition, weak immunity and incorrect water temperature are the three major reasons for fish to get white spot disease. At the same time, when there are other stress inducing conditions in the tank such as incompatible tankmates, it can also cause white spot disease.

  1. Wounds

Fish can get wounded due to different reasons among which fights with fellow tankmates is the most common. Fish fight for territory or to show dominance. Likewise, some fish are territorial and fight with those entering in their area. The presence of fin nippers in the tank also increases the chances of getting nipped and wounded.

Besides these, fish can also get wounded when bumping into aquarium equipment and décor with sharp and rough edges.

Since open wounds invite a number of infections and parasitic infestations, immediate action is necessary. You need to keep the wounded fish in a quarantine tank to make it less vulnerable and susceptible to further uncertainties.

Final words

Knowing the natural behaviour of your fish is extremely important to understand the reason why they are laying at the bottom. Most of the times fish laying at the bottom is not a concerning issue but sometimes it could be because of something serious.

If fish is a bottom dweller or bottom feeder by nature, there is nothing to be concerned about. However, if it is a surface feeder or mid-level swimmer, you need to monitor if it is spending more time at the bottom.

Fish with certain diseases are also found lying at the bottom as an instinct for survival. All you need is to check all the possible reasons and make efforts to correct if anything is wrong.

Subscribe to our Newsletter

Please fill in the form get updates on new articles.

Leave a Reply

Your email address will not be published. Required fields are marked *

16 + 10 =