Your fish’s scales give the creature a shiny, glittering look that catches the eye when the fish are darting around your aquarium.
The outer layer of scales also enables the fish to swim smoothly through the water without resistance and protect the fish’s flesh from injury and attack by parasites and bacteria.
But what if your fish loses some of its scales? Will your fish die without his scales? And do fish scales grow back?
Thankfully, in most cases, your fish’s scales will grow back naturally.
Read this guide to learn everything you need to know about your fish’s scale loss, including how to treat and prevent it.
Why Do Fish Lose Scales?
There are several causes of scale loss in fish, including:
Most of these causes are treatable and preventable, and your fish’s scales will eventually grow back.
Your fish’s scales are pretty strong, but they can sustain physical damage through rough handling or injury in the aquarium.
When moving your fish from their tank during cleaning, for sickness treatment, or relocation to a different aquarium, use a soft net that’s plenty big enough to transport the fish without damaging its scales.
Many fish tank decorations can have sharp edges and rough surfaces, which can cause damage to scales if the fish collide with them. Fish species that typically have erratic swimming patterns are especially at risk of injury, so care should be taken by pet owners when choosing aquarium ornaments.
Aggressive Tank Mates
Scales can be damaged and lost due to fighting and aggression between tank mates, so be careful when choosing fish species for a community tank. For example, some semi-aggressive fish, such as bettas, have tiny teeth that can easily rip off scales.
If you’re not sure whether all the fish you’re considering for your tank will get along, take the time to ask the experts at your local fish store before bringing new friends home.
Be careful not to overcrowd your tank, as that can lead to outbreaks of squabbling and aggressive behavior, especially around feeding times.
All fish species are highly vulnerable to stress caused by incorrect or poor water chemistry, inappropriate water temperature, poor diet, overcrowding, or a bad choice of tank mates.
Stress lowers the fish’s immune system, leaving the creature vulnerable to attack by parasites that could cause scale loss.
Poor Water Quality
The main cause of sick fish and disease in the aquarium is poor water quality. That’s entirely preventable and should never happen in your aquarium, provided you maintain the environment correctly and monitor the water chemistry.
All fish tanks should run an efficient filtration system that circulates the total water volume around the aquarium at least four times every day.
The filter media contains beneficial bacteria that process harmful chemicals, including ammonia, nitrites, and nitrates, keeping the water safe for your fish.
If the water is dirty and overloaded with these dangerous substances, your fish will become sick and might lose some of their scales.
Essential Tank Maintenance
To keep the tank water clean, you must perform a weekly partial water change and vacuum the substrate to remove decaying organic waste.
In addition, the filter media should be rinsed every couple of weeks to prevent it from becoming clogged with sludge that would prevent water from circulating through the unit.
You’ll also need to replace the filter media once a month or so or in line with the manufacturer’s directions.
All fish species are susceptible to bacterial infections, especially if the environment they’re living in is dirty. Bacterial infections come in many different forms, some of which can cause scale loss.
To prevent these disease-causing organisms from getting into your aquarium, keep your tank clean and well-maintained, and quarantine new fish for at least two weeks to ensure they’re healthy before adding them to your main tank.
Protect Your Fish’s Slime Coat
Most fish species produce a slimy coating of mucus that helps protect the scales of fish from infections and parasites. If the slime coat is damaged or in poor condition, scale damage can result.
You can help to promote a healthy fish slime coat by adding a suitable supplement to the aquarium water, following the manufacturer’s directions carefully.
Flicking or Flashing
Fish often rub themselves against objects in the tank in response to skin irritation, usually caused by parasitic diseases, such as White Spot disease or Velvet disease.
That activity often results in missing or damaged scales, as well as minor abrasions and other injuries.
If you notice your fish rubbing against decorations, plants, or the substrate in their aquarium, look closely to see if you can see any tiny white spots or rust-colored dots on the fish’s body or fins.
Fortunately, both those diseases are treatable with an over-the-counter product you’ll get from your local fish store.
Scale Protrusion Disease
Scale shedding disease (or infectious protrusion disease) is a bacterial infection that causes fish to lose their scales.
The usual culprits that cause this disease are typically Pseudomonas fluorescens and Aeromonas hydrophia, which are usually imported with new fish or live food.
In fish with this disease, the scales stick out at an awkward angle and can also drop off. To treat the infection, put the affected fish in a quarantine tank, and use antibiotics, such as chloromycetin or tetracycline.
Do Fish Scales Grow Back?
Thankfully, under certain circumstances, your fish will regrow its missing scales, albeit somewhat smaller than the originals.
However, if the fish suffers heavy scale loss due to a severe fungal infection or some other disease, they might never regrow.
The length of time it takes for the fish to grow new scales depends to a certain extent on the fish species and can take anywhere from several weeks to a few months.
Do Fish Shed Scales Naturally?
Unlike snakes and some other reptiles, fish don’t periodically shed their scales, retaining the same number throughout their lives.
Fish generally only lose scales following injury or disease rather than as part of a natural process.
Can My Fish Survive with Some Missing Scales?
Provided your fish hasn’t lost a vast number of scales, it should be able to survive with a few missing.
I had a large Fancy goldfish that lost a scale, probably due to a collision with a decoration in the tank. The scale never did grow back, but the fish lived quite happily to around 12 years of age with no apparent ill effects.
However, the scales are there to protect the fish from injury and to keep out bacteria and parasites, so a fish with many missing scales could easily succumb to a disease.
In this part of our guide, we answer some of the most frequently asked questions about pet fish losing their scales.
Q: Do damaged fish scales heal?
A: Yes, fish scales eventually heal without intervention from you. However, if the damage to your fish is severe and more than one or two scales are missing, we recommend treating your pet with a preventative antibacterial medication to keep infection away.
Q: How do you treat fish losing scales?
A: The first thing to do is determine why your fish is losing its scales.
If the cause of the scale loss is due to injury, remove the cause. For example, if you have an aggressive fish in the tank that’s attacking another fish, you’ll need to separate them immediately.
If your fish is losing its scales due to disease, diagnose the illness and treat it accordingly. Once the cause of the damage has been dealt with, the fish’s scales should eventually grow back naturally.
Q: Can a fish regrow its scales?
A: Yes. A fish can regrow its scales. However, the rate of scale regrowth depends on the cause of the loss, the species of fish concerned, and its age.
Q: Why are my fish missing scales?
A: It’s not uncommon for pet fish to lose a few scales from time to time. Usually, scale loss occurs as the result of a physical injury, typically if the fish collides with an aquarium decoration or a tank mate.
Rough handling, fighting with other fish, poor water quality, parasite attacks, and skin infections can also cause scale loss.
Q: Can fish live without scales?
A: Yes, your fish can survive without a few scales, provided infection doesn’t set in, and the original injury heals.
In fact, several fish species don’t have scales at all, such as some types of catfish, freshwater blennies, and eels.
Now you know that fish scales can eventually grow back! If you enjoyed our article, please take a moment to share it with other readers.
Fish don’t shed their scales naturally; scale loss is generally caused by traumatic injury or disease. Unless your fish has suffered a significant degree of scale loss, the scales should grow back, although that can take weeks or months, depending on the fish species.
Did your fish lose a few of its scales? What caused the problem, and how did you solve it? Tell us in the comments box below!