What Do Angelfish Do In Fish Tanks? (7 Interesting Facts)

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As I started my angelfish aquarium, I immediately wondered what they could do that other fish don’t. One of the best things I discovered was that angelfish could change their colors. However, over the years, I was amazed by their many other fascinating behaviors.

Here is some information on what angelfish can do in fish tanks:

Angelfish can lock lips as they breed.
Saltwater angelfish can change genders.
Angelfish use their urine to establish territories.
Angelfish can change their colors.
Angelfish are omnivores, meaning that they eat both plant and animal matter.
Some angelfish mate for life.
Angelfish can bite both humans and fish tank companions.

As we move forward, besides the facts above, I will mention how angelfish are likely to react with other living creatures, including fish, shrimp, snails, and plants. Luckily, there are many exciting combinations you can create with angelfish.

Also Read: Facts About Angelfish

What Is Special About Angelfish: What Can They Do?

Many people tend to associate Angelfish with the aggressive behavior for which cichlids are known. But their aggression is just one attribute among many. Angelfish are fascinating creatures that have a plethora of interesting characteristics. For instance:

1. Angelfish Kiss

Angelfish can kiss. Though, it would be more accurate to call it lip-locking. It sounds like the same thing, but it isn’t. In humans, kissing is a sign of intimacy. In Angelfish, lip-locking is categorized as a mating ritual. You will see it in angelfish that have formed breeding pairs.

However, lip-locking can also signify aggression. When angelfish fight, they lock lips. Angelfish will fight over territory and mating partners. The easiest way to differentiate between fighting and mating is to look at their gender.

If the kissing fish are male, they are most likely fighting. But if you have a male and female angelfish, the lip-locking is a sign of mating.

Admittedly, male and female angelfish are more than capable of fighting one another, which is why you should look for additional signs of mating. Mating pairs will search for and then clean flat surfaces where the female can lay its eggs.

Naturally, if your angelfish are mating, the female will eventually lay eggs. You can identify her by the tube near the anal and ventral fin. The female’s tube is thicker than the male’s tube.^[1] If that isn’t telling enough, at some point, the female angelfish will swell with eggs.

If that phenomenon interests you, I have dedicated an entire article to it. I also elaborated on a few other signs that may indicate whether your angelfish are fighting or mating.

2. Some Angelfish Can Change Genders

Did you know that angelfish can change their gender? Most people own P. Scalare, also known as the freshwater angelfish.^[2] Centropyge Ferrugata, called ‘Rusty Angelfish’ by aquarists, is a saltwater variety.^[3]

The freshwater angelfish cannot change its gender. However, this phenomenon has been observed in its saltwater counterpart. Studies that explored the issue showed that a situation in which two males cohabited would compel one of the males to change his gender.

If the males competed, the loser would become subordinate to the winner. As a result, the loser would start by performing rituals that aquarists associate with female angelfish. In the long run, the male angelfish would become female.^[4]

3. Angelfish Urinate To Establish Hierarchy

Angelfish cannot talk. However, they can still communicate. Angelfish live in hierarchical communities. When an angelfish dominates its neighbors, it uses the chemical signals in the bile and urine it releases to convey its social status.

This is why large and frequent water changes encourage violence in angelfish tanks. A study revealed that frequent water changes tended to dilute the chemical signals in the water.^[5]

This destroyed the hierarchy in the aquarium, which, in turn, drove the angelfish to fight one another anew in the hopes of establishing their dominance.

If you have ever wondered why a significant water change in an angelfish tank is often followed by a spike in violence, this is the reason why. You have essentially compromised each fish’s ability to identify the head of their community.

4. Angelfish Can Change Colors

People buy angelfish because they are active creatures with vibrant colors. But those colors can change. Angelfish have cells called chromatophores and iridophores that produce their stunning colors. With the melanosomes and melanin comes the ability to change color.^[6]

They can change color for many reasons, including environmental changes, stress, fear, sickness, and changes in the lighting, to mention but a few. Some angelfish will change specific markings and colorations as they mature.

For instance, a young angelfish’s black stripes may become yellow as it grows older. Others will grow pale in response to a severe illness. You can’t predict the changes you will see until they happen.

I actually dedicated an entire article on how angelfish change their colors. I even wrote an article where I mainly discussed their stipes, which can frequently fade and then return to normal. Sometimes, it means that your Angelfish is suffering.

5. Angelfish Eat Both Plant And Animal Matter

Are freshwater angelfish omnivores or carnivores? It’s a little bit of both. In the wild, they are primarily carnivorous, surviving on insects, bloodworms, and shrimp.

But in captivity, they are omnivorous.^[7] You have to give them a balanced diet that includes flakes and pellets. In an aquarium, they will attack and eat smaller fish, especially if those fish can fit in the angelfish’s mouth.

6. Angelfish Mate For Life

Many people think that fish are enthusiastic breeders who are always looking for a new companion to mate with. And that is true with some species. But that isn’t the case for angelfish.

They form monogamous pairs.^[8] They typically mate for life. In some situations, when one Angelfish dies, the mate will remain celibate for the rest of its life.^[9]

That isn’t always the case. Some angelfish will mate with multiple partners over the course of their lifespan.^[10] Female angelfish have been known to attack male angelfish that they mated with in the past but then rejected later on.

Therefore, you shouldn’t expect every single mating pair in an angelfish tank to stay together forever. However, monogamous pairs are more common than the alternative. This makes angelfish unique in that regard.

7. Angelfish Can Bite

When you think of small fish, you tend to think of small teeth. But angelfish are not small fish. They are actually quite large. Some freshwater angelfish can grow up to 10 inches long.

With the size comes the teeth to match. They usually bite when stressed, especially when the water parameters are incorrect, as I explained here. Yet, they do not pose a threat to human’ hands.

Do Angelfish Eat Other Fish?

Angelfish eat other fish. They are cichlids, which means that they have an aggressive streak. Admittedly, they are not quite as aggressive as other cichlids. But they have a reputation for eating small fish.

Like most fish, angelfish are opportunistic. They will eat anything they can fit in their mouths. But many fish have peaceful temperaments that enable them to coexist with smaller creatures.

They may eat the odd fish here and there, but they won’t make it a habit to attack their smaller tankmates. However, you cannot trust angelfish to behave. If your angelfish share their tank with smaller fish, you must assume that the angelfish will eventually eat the smaller fish.

If you are interested, here is an article where I discussed the best and worst angelfish tankmates. In there, you’ll find what species of angelfish will probably ignore eating. These will perfectly fit in your aquarium.

Do Angelfish Eat Snails?

Angelfish do not have a reputation for eating snails, not even smaller pest snails. Naturally, there are plenty of exceptions. But unless you have crushed the snails before feeding them to the angelfish, the creatures will not make it a habit to eat the snails in the tank.

Generally, it depends on the type of snail. Angelfish may harass larger snails.^[11] Luckily; most snails do not pose a threat to Angelfish, regardless of their size. Snails do not have the tools required to harm angelfish.

Of course, Angelfish can still bully their snail neighbors to death. If you’re struggling to identify a snail species that can survive in an angelfish tank, try Malaysian Trumpet Snails.

Malaysian Trumpet Snails are a great addition to an angelfish tank because they spend a lot of time burrowing in the substrate where angelfish cannot reach them. They can create entire colonies inside the substrate.

On that topic, here is an article where I discussed whether angelfish eat snails. In there, I listed the snails that angelfish will probably eat and those that they usually ignore.

Do Angelfish Eat Plants?

Angelfish are omnivores. They can eat vegetables. But their diet primarily consists of meat. They have no interest in plants. If your angelfish are seemingly eating the foliage in their surroundings, four reasons could explain their behavior:

Age – If your angelfish are young, their decision to eat the foliage shouldn’t surprise you. Like human children, young angelfish are always trying new things. They may nibble on the plants out of curiosity. But they won’t make it a habit to eat them.

Diet – Angelfish may turn to plants because you have failed to feed them appropriately. They may also nibble on the plants because they need to fill a gap in their diet. This will stop once you fix their dietary issues.

Preference – Any experienced aquarist you consult will tell you that fish are unpredictable creatures. You cannot trust them to behave according to the guides that some fish stores sell. Some angelfish eat plants simply because they want to. Others may destroy the foliage out of boredom. That doesn’t mean they have a craving for plant matter.

Breeding – When angelfish are breeding, they will find a suitable surface and clean it. You should consider the possibility that your angelfish have taken a liking to a particular plant because they want to use it as a breeding ground, not because they want to eat it.

If your angelfish is damaging your plants, here is an article where I discussed how to stop them from doing so. In there, I also listed the best types of plants for angelfish.

Do Angelfish Eat Shrimp?

Angelfish will eat shrimp. Because they are opportunistic eaters, they will eat whatever they can fit in their mouths, including shrimp. Angelfish can grow to a size of 6 inches. To these creatures, shrimp are just prey.

Angelfish that do not care for shrimp as a potential food source are just as dangerous because they can still bully your shrimp to death. Some shrimp, such as the Macrobrachium species, are safe because they are so large.^[12]

In fact, Macrobrachium shrimp can kill fish. But what would be the point of adding a shrimp that can kill your angelfish? On the other hand, common species like Cherry shrimp and Amano shrimp are unlikely to survive in an angelfish tank.

You can always take steps to safeguard vulnerable shrimp. One option is to introduce the shrimp first. That way, the angelfish are less likely to perceive the shrimp as invaders in their territory.

You also have the option of adding plants and decorations to the aquarium. But even the presence of suitable hiding places cannot guarantee the safety of the shrimp.

For your convenience, here is an article where I discussed whether angelfish eat shrimp. In there, I listed the most common types of aquarium shrimp and mentioned how angelfish would treat them.

Also Read: Angelfish Water Current

Conclusions

Angelfish are beautiful fish that are an absolute blast to watch. Unfortunately, they can be aggressive towards other aquarium inhabitants. They may eat other species. But they don’t have the reputation of eating every creature in sight.

Angelfish are omnivores so they can eat vegetables. But their diet primarily consists of meat. They have no interest in plants. Angelfish do not eat snails or plants, but they do eat shrimp, especially shrimp fry that easily fit in their mouths.