Crabs, whether land or aquatic, will eat just about anything. This makes them opportunistic eaters and fascinating creatures to many people. They vary in sizes, from those that are so small you can barely see them to the crab giants that you will be more likely to see in a horror movie than reality. Although there are many crab species, over 4,000 of them, their eating habits remain similar.
You can find crabs on the beach next to the ocean, as well as the aquatic crabs that live on the ocean floor. It’s worth noting that some crabs can also be found in fresh waters, particularly lakes and rivers.
Being opportunistic eaters, they more often than not won’t differentiates between what they eat, as long as it’s edible and nutritional enough for them.
That being said, if there’s some animal or plant leftovers, or any matter that is in the process of decomposing, you can bet that they will want to eat it.
If you’re reading this article right now, chances are that you want to grow crabs and sell them, or keep one as a pet inside your aquarium. Whatever may be the case, if you want those crabs to breed properly you will want to establish enough nutrients for them.
One of the best ways to take care of crabs is to feed them properly. But, that’s not easy. What will crabs eat in the artificial conditions that you created for them? Luckily, you’ve come to the right place.
In this article, we’re going to explore what crabs eat, whether they are pets or crabs you want to grow and breed. After reading this, you’ll be able to pick a diet for them that will be the most fruitful for you.
You’ll also learn about different ecosystems that crabs reside in and how that affects their eating habits.
Although most crabs will eat anything that seems nutritional to them, different species have different eating habits. In commercial conditions, there are 40 to 50 species that are sold and grown as well as traded.
Eating Habits of Wild Crabs
To understand crabs kept in captivity, it’s also necessary to understand the crabs that live in the wild. It’s worth understanding that they will feed on dead leftovers of larger food.
But, if the food is lacking they will hunt on their own. More often than not, you’ll catch them eating plant matter that they come across, algae, and other scraps on the seafloor.
When they hunt, they will feed on smaller fish, shrimp, seashells, and sea snails, whatever they can catch in time without losing too much energy.
However, different crab species will prefer a specialized diet and not just eating anything they find on the seafloor.
There are even crabs that show only carnivorous preferences and will get aggressive towards the smaller fish to get what they need. Some carnivorous crabs will even eat other crabs if they’re smaller and can be caught.
Some crabs like the King crab were “favored” by evolution to have easier time hunting. One of their claws is significantly larger than the other which allows them to crush and immobilize the prey they catch. Scavenger crab species are a different story and will eat whatever dead matter they find on the floor.
It’s worth mentioning that many crabs that live on the shores and rarely enter the water will prefer eating plant-based food rather than animals. Why they prefer this is unknown, but they’ll enjoy eating any organic plant material that they can come across like the withering flowers, leaves, roots, fruits, seeds, and grains.
Editor’s notes: It’s hard to expect home-owned crabs to have hunting preferences, or eat the same food as the wild crabs. Being kept in captivity leads to different feeding habits, so you have to be careful.
What Do Commercial Crabs & Pet Crabs Eat?
Let’s discuss what crabs eat in commercial and home settings. Commercial crabs are those that are raised to be sold, traded, or used as food for some other animals like turtles. Both aquatic and terrestrial crabs are kept in captivity and you should establish good conditions for both.
Given that one kind of crab is aquatic and the other will live in a terrarium or some other dry shelter, it’s necessary to provide them the right source of food that won’t exhaust them or cause them health problems.
Even though crabs are generally considered to be scavengers, in captivity the rules change, especially as bad food can cause them to get ill and die. Both groups of crabs get the most nutrients from calcium-rich foods, proteins, and sometimes fruits. Let’s take a look at what they eat based on where they live.
Crabs in Aquariums
Crabs in an aquarium need a varied diet. If possible, you should find a way to feed them outside the water tank. That’s because eating too much food in the aquarium can lead to contamination of the water and eventual poisoning of the crabs.
So what should crabs in the aquarium eat?
- Calcium-rich nutrients
- Vegetables and grains
- Protein-rich foods (remember that there’s both plant-based and meat-based protein)
With these ingredients, your aquatic crabs are guaranteed to have a varied diet that will help them grow and stay healthy.
You may notice that we didn’t mention a fruit-rich diet. First, even though crabs can benefit from eating fruits, it can be difficult for them as fruit needs to be prepared in a special way (not too much sugar, peeled, cut, and so on).
Fruit is rich in sugar and watery conditions, even with a good filter, they can wreak havoc in your aquarium and damage all flora and fauna inside. Fruit can attract bacteria that reproduce in a sugary environment much faster than normal, which could lead to contamination.
Sugar can disrupt the neutral pH level of your tank and make it acidic, which can lead to a loss of oxygen in the water, ultimately causing the fish and crabs to die. You should be careful about how you feed the crabs.
Here are the vegetables you can feed them:
- Green pea
- Green beans
A lot of this food is rich in vitamin C, vitamin E, vitamin K, as well as minerals like Zinc, Potassium, Magnesium, Manganese, and many more others, and will make a great diet for your crabs. This food is also rich in plant-based protein. Here’s a list of other proteins they can eat:
- Raw beef
All of these do contain some calcium in differing amounts. However, if you’re interested in other calcium-rich foods that your crabs can eat, take a look at the following ingredients:
- Oyster shells
If you keep crabs in captivity, there are special packages of balanced commercial foods that are rich in all the aforementioned ingredients, vitamins, and minerals which crab can eat in large amounts to grow big and strong.
Most people who grow and trade crabs will feed them dry pellet foods that can be found in a different wholesale and commercial shops. The good news is that you can freeze the crab food so you can stack up on supplies. If you’re undecided, you can try API Fish Food flakes or Aqueon Shrimp Pellets.
Terrestrial crabs kept in captivity are a little more flexible when it comes to their feeding habits. They mostly are kept in terrariums or some other types of empty tanks where they have everything they need to survive, as long as you provide them with the necessary ingredients.
That being said, all the applied proteins, plants, calcium-rich foods that you’d normally use to feed your aquatic crabs apply to feed the terrarium-based crabs. Still, their diet can be more sugary and richer in some other types of vitamins.
Terrestrial crabs can eat fruits more easily. As they don’t reside in water which can easily be contaminated, the same doesn’t apply to terrestrial conditions. There’s a variety of fruits that terrestrial crabs can eat, which includes:
It’s of utmost importance to give crabs peeled fruit, as that can prevent intoxication and poisoning. You may not need to peel all the food but with peaches, plums, and berries, it’s the best to peel them. Also, try cutting them into tiny pieces so that your pet crab can consume them more easily.
What Foods to Avoid Feeding Your Crabs?
There are some foods that you should try to avoid. Such food includes:
- Overly salty, oily, and sugary foods.
- Starchy vegetables such as potatoes. Starchy vegetables like pea and beans are acceptable in small amounts, but nothing excessive.
- Although dairy products are rich in calcium, you should avoid feeding your crab pet with it.
- Avoid carbs like chips, pretzels, and cereals, as they may not have enough nutritional value for the crabs you’re trying to look after, and could also harm them in the long term.