Learn the top 10 reasons fish die and how to prevent it. Keep your fish happy and healthy!
Why Fish Die Early? Discover the top 10 reasons and learn essential prevention tips to keep your fish thriving and happy in their aquatic home!
Why Do Fish Die Early in Aquarium?
Fish mortality in Aquarium is normal, but when large numbers of fish are observed dying at once it can be cause for concern. Understanding the primary causes of fish kills can help prevent future losses.
When observing an aquarium, the first thing to ask yourself is how many fish are dying and for how long. This information will help to determine whether the death is acute or chronic.
1. Improper Tank Setup
Tanks that lack adequate bracing can have serious consequences when moved. Insufficient bracing can lead to tank sides caving in, heavy bowing of glass or acrylic and even rupture of liners.
Rapid water changes can disrupt a tank’s carefully balanced chemistry and shock fish, causing them to die. Regular testing of nitrate and ammonia levels will help keep water quality in balance. Slowly changing small amounts of water is the best way to change tank chemistry. A full tank cycle takes time. It is important to follow the instructions for cycling your tank correctly.
2. Improper Water Changes
Water chemistry changes continually as fish excreta, uneaten food and dead plant matter change the water. This is a normal part of aquarium ownership and can be minimized with routine testing and careful tank management.
However, rapid water changes will disrupt this delicate balance and shock the fish, causing them to die. To prevent this, do your water changes slowly and only when necessary. This will help the fish acclimate to the sudden changes in chemistry. This will also protect the health of the fish and prevent disease.
3. Poor Water Quality
Fish are exposed to a variety of disease-causing bacteria, viruses and fungi on a daily basis. Under optimal conditions healthy fish can fight off most of these organisms.
However, when water quality deteriorates, these organisms have an advantage and begin to reproduce quickly. This can lead to a toxic build-up of dissolved impurities. Regular water changes restrict the accumulation of toxins and improve water quality.
4. Cold Water
Fish kills are often the first warning signs of pollution events. They also indicate that a body of water may be overcrowded and that competition for food is too intense.
Fish deaths in ponds are common, especially when the weather turns cool. This causes a rapid turnover in the pond, where the lower layer with low oxygen and decomposing biological material mixes with the upper layer of water. These events can cause fish to die if their respiratory system is stressed by the change in conditions.
5. Excessive Heat
While it is normal to see the odd dead fish in a pond, large numbers of dead fish could mean that something is wrong. Stress in fish acts like a ticking time bomb, slowly eroding their health until they simply can't cope anymore.
A heat wave is a prolonged period of extreme hot weather combined with excessive humidity. This can lead to disease-related deaths in fish if water parameters aren't properly monitored, tank community and diet aren't taken into account and new fish purchases are made without careful consideration.
6. Poor Airflow
When there is a problem with the water quality or a disease, fish can die. However, fish can also die because they are living in a tank that doesn’t provide enough oxygen.
A lack of dissolved oxygen can be caused by an overcrowded aquarium or by a dirty filter. It can also be the result of poor ventilation in a room or because a piece of equipment has been broken. These are all very common causes of fish deaths.
7. Algae Blooms
Algae are simple, photosynthetic plants that form the base of most aquatic food webs and provide a significant amount of the Earth’s atmospheric oxygen. But when favorable environmental conditions exist, they can grow out of control and produce a dense mass known as an algae bloom.
Some types of algae blooms produce toxins that can cause illnesses in humans, animals and plants. These events are called harmful algal blooms, or HABs. Learn more about them here and visit our Fish Kill & Algal Bloom dashboard to report a bloom.
8. Water Temperature Changes
Most ponds will experience a natural die-off each year as a means of thinning an overcrowded population. This occurs during periods of cloud cover which restricts sunlight penetration, causing the algae in the deeper water to deplete oxygen levels. Look for signs such as lesioning, gill hemorrhages or distended fins.
A sudden change in water temperature can cause a fish to suffocate as it struggles to breathe. This is especially true for species that live in seasonal climates. This type of event is exacerbated by climate warming.
9. Oxygen Levels
As a general rule, warm water can only hold so much dissolved oxygen. During the day plants and algae put oxygen into the water via photosynthesis. But during the night, they consume oxygen along with all the critters that are in the water. If demand exceeds supply, oxygen levels begin to decline and a fish kill can occur.
When oxygen levels drop, fish exhibit a number of signs including labored breathing and rapid movement of their gills. They also may be seen "gasping" at the surface of the water.
10. Stress
Stress is a common cause of fish dying early. Just like humans, fish can be stressed by environmental factors. Some common sources of stress include aggression, poor water quality, and overcrowding.
Pesticides can also be a cause of fish kills. Fish will typically die of poisoning first and smaller fish tend to be affected more than larger ones.
Keeping fish is a fun and rewarding hobby, but it can be frustrating when one or more of your fish keep dying unexpectedly. Getting to the bottom of why your fish are dying early can help ensure your tank is healthy and safe for your fish.
